Transmission of Time and Code Multiplexed Pilot Sequences

Abstract

Techniques are provided for transmitting, receiving, and adjusting pilot sequences and for evaluating channel characteristics. The pilot signal may include a pilot sequence, which includes at least one first set of equally spaced symbols (S A ) and at least one second set of equally spaced symbols (S C ) and at least one second set of equally spaced symbols (S AC ) symbols are arranged in at least one first set of equally spaced symbols (S A At least one second set of equally spaced symbols (S C ) and at least one first set of equally spaced symbols (S ) are arranged such that each first set of equally spaced symbols represents a respective first code. A ), and at least one second set of equally spaced symbols (S E Each first code and each second code can be selected from the set of codes (S A , S C ) matches at least one other code (S E , S G ) may be selected from a set of codes that are orthogonal to the code transmitted by the transmitter. The same technique of transmitting a sequence using a code that is orthogonal to the code transmitted by the transmitter may be implemented in another transmitter.

Description

Technical Field

[0001] The present invention relates to a transmitter (e.g., a wireless transmitter such as an optical transmitter), a receiver, and an adjuster, and related methods. Techniques are provided for transmitting, receiving, and adjusting a pilot sequence and for evaluating channel characteristics.

Background Art

[0002] In modern telecommunication systems, so-called estimation sequences / symbols are often used to simultaneously estimate the characteristics of physical transmission channels for several users. For this purpose, one or several of these sequences that must be known to the transmitter and the receiver are transmitted via the channel, and the distortion characteristics of the channel and the crosstalk between users are derived from the received signal. In this case, the sequences used should have certain characteristics, i.e., the orthogonality of the sequences with respect to each other is meaningful and common because it can mathematically cleanly separate the parallel estimation processes. The present invention mainly focuses on systems operating in the time domain using binary pulse amplitude modulation (PAM-2). Here, binary estimation sequences are also required. Specifically, the PM-PHY of the future standard IEEE802.15.13 is under consideration. So far, the transmitter and the receiver have had to operate at the same clock rate to perform channel estimation. However, it would be meaningful if the receiver could operate at a lower clock rate for some time and still perform channel estimation in order to save energy. However, in this case, the orthogonality between sequences of different clock rates must be maintained.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Research in the technical literature has not provided any known solutions to this particular problem. Closest to the technical point of view is the orthogonal variable spreading factor (OVSF) code [1, Chapter 4.3]. They are used for bandwidth spreading in CDMA systems. However, they are based on the Hadamard matrix and due to their poor correlation characteristics, they are only suitable for a limited range for desired channel estimation.

[0004] References [1] "3GPP (Registered Trademark) TS25.213, v16.0.0, Spreading and modulation (FDD)", Tech. Rep., 2020 [2] Presentation "Time Domain MIMO Channel Estimation for LiFi", Jonathan Schostak, 2021 [3] R. Gold, "Optimal Binary Sequences for Spread Spectrum Multiplexing", IEEE Transactions on Information Theory, vol. IT-3, no. 4, 1967

Means for Solving the Problem

[0005] According to one aspect, a transmitter configured to transmit a pilot signal including a pilot sequence is provided, the pilot sequence including at least one first set of equally spaced symbols, and at least one second set of equally spaced symbols, wherein the symbols of at least one second set of equally spaced symbols are inserted between the symbols of at least one first set of equally spaced symbols, and including a plurality of symbols having The transmitter at least one first set of equally spaced symbols such that each first set of equally spaced symbols represents a respective first code, and At least one second set of equally spaced symbols is selected such that each second set of equally spaced symbols represents a respective second code. configured to select The transmitter is configured to select each first code and each second code from a set of codes where each code of the set of codes is orthogonal to at least one other code of the set of codes.

[0006] The transmitter can transmit a pilot sequence at a symbol rate selectable between a first symbol rate and a second symbol rate that is a multiple of the first symbol rate according to a predetermined integer factor, where the time duration of the first pilot sequence is the same as the time duration of the second pilot sequence, and the sum of the number of symbols of at least one first set of equally spaced symbols and the number of at least one second set of equally spaced symbols is a multiple of at least one first set of equally spaced symbols according to a predetermined integer factor, and the predetermined integer factor is greater than 1. The predetermined integer factor may be 2 or a power of 2 raised to an integer exponent. Within the pilot sequence, multiple symbols may be arranged according to a regular time base.

[0007] The transmitter can transmit a pilot signal including a pilot sequence, and the transmitter is configured to select a pilot sequence from among a plurality of pilot sequences, and the plurality of pilot sequences include at least a first pilot sequence, a second pilot sequence and includes The first pilot sequence includes a plurality of symbols of the first pilot sequence. The second pilot sequence includes the symbols of the first pilot sequence and additional symbols of the second pilot sequence inserted between the symbols of the first pilot sequence. The transmitter The symbols of the first pilot sequence include at least one first set of equally spaced symbols, each first set of equally spaced symbols representing a respective first code, and the symbols of the second pilot sequence include at least one second set of equally spaced symbols, each second set of equally spaced symbols representing a respective second code different from each first code can be defined, The transmitter can select each first code and each second code from a set of codes where each code of the set of codes is orthogonal to at least one other unselected code of the set of codes.

[0008] The plurality of pilot sequences may include at least one third pilot sequence, the third pilot sequence including the symbols of the first pilot sequence and the symbols of the second pilot sequence, with one or more additional symbols inserted between the symbols of the first pilot sequence and the symbols of the second pilot sequence, such that the transmitter transmits pilot sequences from at least the first, second, and third pilot sequences. The first pilot sequence may include a first set of equally spaced symbols representing a first code, and a second set of equally spaced symbols representing a second code and, The second pilot sequence may include a first set of equally spaced symbols representing a first, and a second set of equally spaced symbols representing a second code and, the second pilot sequence also includes a further set of equally spaced symbols representing a third code.

[0009] The transmitter can transmit a first sequence at a first symbol rate and a second sequence at a second symbol rate that is higher than the first symbol rate. The time length of the first pilot sequence is the same as the time length of the second pilot sequence, and the second pilot sequence has a total number of symbols that is greater than the total number of symbols of the first sequence. The second symbol rate can be a multiple of the first symbol rate. The time length of the first pilot sequence is the same as that of the second pilot sequence, and the second pilot sequence has a total number of symbols that is a multiple of the total number of symbols of the first sequence. The transmitter can transmit a first pilot sequence at a first symbol rate and a second pilot sequence at a second symbol rate that is a multiple of the first symbol rate according to a predetermined integer coefficient. However, the time length of the first pilot sequence is the same as the time length of the second pilot sequence, and the sum of the number of symbols of at least one first set of equally spaced symbols and the number of at least one second set of equally spaced symbols is a multiple of at least one first set of equally spaced symbols according to a predetermined integer coefficient, and the predetermined integer coefficient is greater than 1. The predetermined integer coefficient may be 2 or a power of 2 raised to an integer exponent.

[0010] The transmitter can receive signaling to select between at least one first symbol rate and at least one second symbol rate. Within the selected pilot sequence, a plurality of symbols may be arranged according to a regular time basis. Within the second pilot sequence, the symbols of the first pilot sequence and additional symbols inserted between the symbols of the first pilot sequence are arranged according to a regular time basis.

[0011] The transmitter may be such that when at least one first code represented by at least one first set of equally spaced symbols and at least one second code represented by at least one second set of equally spaced symbols are interleaved with each other, a composite code orthogonal to an additional composite code formed by at least one additional code orthogonal to at least one first code and a second additional code orthogonal to at least one second code is formed. As a result, within the additional composite code, at least one first additional code and at least one second additional code are each interleaved with each other such that the positions of the entries of each first code and the entries of each orthogonal first additional code correspond.

[0012] The transmitter may be such that when the first binary value among its binary values is indicated by 0, the other binary values among its binary values are 1, and the binary values are represented in hexadecimal, the composite code and / or the additional composite code may be selected from the following codes, or their downsampled versions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he composite code may be stored in a memory unit, and the transmitter can retrieve the code represented by the selected pilot sequence according to the composite code. The composite code may correspond to a second pilot sequence or correspond to a second pilot sequence interleaved with other discarded codes.

[0013] The transmitter includes or can access a memory unit storing a plurality of codes, and the codes are stored according to a format in which a plurality of codes are interleaved with other codes to form a composite code. As a result, the code selected for the selected pilot sequence is obtained from the selected position of the composite code. For each code used for each set of equally spaced symbols, the transmitter which composite code among the plurality of stored composite codes is selected, and which shift the interleaved code selected within the selected composite code has, in order to identify the set of equally spaced entries within the selected composite code from which the symbols of the selected sequence are obtained can receive signaling from an adjuster indicating this.

[0014] The transmitter includes or can access a memory unit storing at least V different pilot sequences, Configured to define P pilot sequence slot positions within the same pilot signal to transmit P different selected pilot sequences, each of the P selected pilot sequences is transmitted at one of the P pilot sequence slot positions, Each of the P selected pilot sequences is obtained from at least V different stored pilot sequences, as a result, at least P*V possible combinations are implied between the P pilot sequence slot positions and the at least V different stored pilot sequences, and the at least P*V possible combinations are enumerated according to a predetermined order, The transmitter is further configured to receive signaling that selects P selected combinations that associate the P selected pilot sequences transmitted at each of the respective P pilot sequence slot positions. The at least P*V possible combinations may be enumerated according to a combination index, and the combination index of each of the P selected combinations is obtained from the signaled index. The signaled index can encode a number between 0 and P*V - 1. The at least V different stored pilot sequences may be enumerated from 0 to V - 1, the P pilot sequence slot positions are enumerated from 0 to P - 1, and the P selected combinations are obtained by performing an integer division between the signaled index and P or V, as a result, each position is associated with a combination obtained from the integer result of the integer division and the remainder of the integer division.

[0015] The transmitter may be further synchronized with a second transmitter, such that both the transmitter and the second transmitter have at least one set of equally spaced symbols transmitted by the transmitter being simultaneous with at least one set of equally spaced symbols transmitted by the second transmitter, and at least one set of equally spaced symbols transmitted by the transmitter represents at least one code orthogonal to at least one code represented by at least one set of equally spaced symbols transmitted by the second transmitter, and transmit a pilot sequence interleaved with each other. Each entry of each code of the set of codes can encode a binary value that is either one first binary value or one second binary value different from the first binary value. Each code within the set of codes can have a "balanced property" such that, for each code within the set of codes, the number of entries having a first logical value is the same as the number of any other logical value.

[0016] The transmitter can transmit a selected pilot sequence according to pulse amplitude modulation (PAM) modulation. The PAM modulation may be PAM-2 modulation. The selected pilot sequence may be modulated according to the modulation such that each symbol is represented by physical emission at a predetermined wavelength for a predetermined time slot if it is the first binary value, or by the absence of emission for a predetermined time slot if it is the second binary value. The transmitter can detect the reception of a beacon signal, synchronize with the beacon signal, and then transmit a selected pilot sequence or a second pilot sequence. The transmitter may be a wireless transmitter. The transmitter may be an optical transmitter. The transmitter may be a radio frequency (RF) transmitter. The transmitter may be a wired transmitter. The transmitter may be a mobile device. The transmitter may be a fixed-position device. The transmitter may be wired to a regulator to receive signaling from the regulator.

[0017] According to one aspect, there is provided an adjuster configured to adjust the simultaneous transmission of different pilot sequences of pilot signals transmitted by a plurality of transmitters, the plurality of transmitters including at least one first transmitter and one second transmitter, The adjuster is configured to assign to the first transmitter a plurality of codes including at least one first code and at least one second code, the at least one first code and the at least one second code being codes of a set of codes, and configured to assign to the second transmitter a plurality of additional codes including at least one first additional code and at least one second additional code, the at least one first additional code and the at least one second additional code being codes of a set of codes, the at least one first additional code being orthogonal to the at least one first code, and the at least one second additional code being orthogonal to the at least one second code, configured to select, for each transmitter of the plurality of transmitters, at least one symbol rate from a plurality of symbol rates including at least one first lower symbol rate and one second higher symbol rate, configured to signal to the first transmitter the at least first code and the at least one second code assigned to the first transmitter, and to signal to the second transmitter the at least one first additional code and the at least one second additional code assigned to the second transmitter, configured to signal the selected symbol rate to each transmitter, such that when the first symbol rate is selected for the first transmitter, the first transmitter transmits a first pilot sequence including a first set of equally spaced symbols, ​When a second symbol rate is selected for the first transmitter, the first transmitter transmits a second pilot sequence that includes at least one first set of equally spaced symbols, at least one first set of equally spaced symbols, and at least one second set of equally spaced symbols interleaved with the at least one first set of equally spaced symbols. When a first symbol rate is selected for the second transmitter, the second transmitter transmits a first additional pilot sequence that includes at least one first additional set of equally spaced symbols. When a second symbol rate is selected for the second transmitter, the second transmitter includes at least one first additional set of equally spaced symbols, at least one first set of equally spaced symbols (S EG ) and at least one second additional set of equally spaced symbols interleaved with the at least one first set of equally spaced symbols in a second additional pilot sequence (S EG ) is transmitted. The regulator can transmit a beacon signal to a plurality of transmitters so that the first transmitter and the second transmitter are synchronized with the beacon signal.

[0018] For each code used, the regulator which composite code among a plurality of stored composite codes is selected, and To identify the set of equally spaced entries within the selected composite code from which the symbols of the selected sequence are obtained, which position the interleaved code selected within the selected composite code has Signaling indicating can be transmitted to each transmitter. For each transmitter, P > 1 pilot sequence slot positions within the same pilot signal may be defined to transmit P different selected pilot sequences, each at one of P pilot sequence slot positions. Each of the P different selected pilot sequences is obtained from at least V > 1 different stored pilot sequences, as a result, at least P*V possible combinations are implied between the P pilot sequence slot positions and at least V different stored pilot sequences, and at least P*V possible combinations are enumerated in a predetermined order. The conditioner is further configured to select, for the transmitter, P combinations that associate the P selected pilot sequences transmitted at each of the respective P pilot sequence slot positions, and to signal the P selected combinations to the transmitter.

[0019] At least P*V possible combinations may be enumerated according to a combination index, and the combination index of each of the P selected combinations is signaled as the signaled index. The signaled index can encode a number between 0 and P*V - 1. At least V different pilot sequences may be enumerated from 0 to V - 1, the P pilot sequence slot positions may be enumerated from 0 to P - 1, and the P selected combinations are obtained by performing an integer division between the signaled index and P or V, as a result, each position is associated with a combination obtained from the integer result of the integer division and the remainder of the integer division. The conditioner may be wired to the first and second transmitters. The conditioner may not be wired to a plurality of transmitters, the conditioner is wired to at least one relay device, and the conditioner is configured to transmit signaling to a plurality of transmitters via at least one relay device.

[0020] According to one aspect, a receiver is provided for receiving a pilot signal transmitted by a transmitter, the receiver is configured to obtain phase information of the pilot signal from a pilot sequence within the pilot signal, and the pilot sequence includes a plurality of sets of equally spaced symbols interleaved with each other. The receiver performs an evaluation operation that evaluates the correlation between the pilot sequence and pre-stored versions of multiple sets of symbols at equal intervals, thereby obtaining phase information from the determination of the set of codes having the highest correlation with the pilot sequence. The receiver is configured to determine the set of codes having the highest correlation with the pilot sequence.

[0021] The receiver cross-correlates the pilot sequence with multiple sets of symbols at equal intervals, thereby being able to find the set of codes that maximizes the cross-correlation in order to obtain phase information from the set of codes that maximizes the cross-correlation. Each set of symbols at equal intervals can have an offset within the pilot sequence that indicates the phase of the pilot signal. The pilot sequence may be transmitted at a symbol rate selected from multiple symbol rates. The pilot sequence at the first symbol rate is a first pilot sequence having at least one first set of symbols at equal intervals, and the pilot sequence at a second symbol rate higher than the first symbol rate is a second pilot sequence having at least one first set of symbols at equal intervals interleaved with at least one second set of symbols at equal intervals. The receiver is selectively In the case of receiving only the first pilot sequence at the first symbol rate, sample the pilot sequence at the first symbol rate, thereby evaluating the correlation between the first pilot sequence and the pre-stored version of at least one first set of symbols at equal intervals. In the case of receiving the second pilot sequence at the second symbol rate Sample the second pilot sequence at the second symbol rate and evaluate the correlation between the second pilot sequence and the pre-stored version of at least one first set of symbols at equal intervals interleaved with at least one second set of symbols at equal intervals, or Sample the second pilot sequence at the first symbol rate and evaluate the correlation between the second pilot sequence and a pre-stored version of at least one first set of symbols that are equally spaced. is configured as follows.

[0022] The receiver can select the first symbol rate when the energy storage level falls below a predetermined energy threshold and select the second symbol rate when the energy storage level exceeds the predetermined energy threshold. The pilot sequence may be superimposed on an additional pilot sequence transmitted by a second transmitter, and the additional pilot sequence is at least a first additional pilot sequence transmitted at the first symbol rate, the first additional pilot sequence including at least one first additional set of equally spaced symbols, the first additional pilot sequence, and a second additional pilot sequence (S EG ) transmitted at a second symbol rate higher than the first symbol rate, the second additional pilot sequence (S EG ) including at least one first additional set of equally spaced symbols and at least one second additional set of equally spaced symbols interleaved therewith, the second additional pilot sequence (S EG ) is one of them, at least one first set of equally spaced symbols represents at least one first code orthogonal to at least one first additional code represented by at least one first additional set of equally spaced symbols, at least one second set of equally spaced symbols represents at least one second code orthogonal to at least one second additional code represented by at least one second additional set of equally spaced symbols, The receiver performs an evaluation operation to evaluate the correlation between the additional pilot sequence and a pre-stored version of an additional set of symbols at equal intervals, thereby obtaining phase information from the determination of the additional set of codes having the highest correlation with the pilot sequence, and is configured to determine the set of codes having the highest correlation with the pilot sequence.

[0023] The receiver can evaluate channel information from the received signal received from a plurality of pilot signals transmitted simultaneously by a plurality of transmitters, the plurality of transmitters including at least a first transmitter and a second transmitter, and as a result, the first pilot signal transmitted by the first transmitter is at least a first pilot sequence at a first symbol rate, the first pilot sequence including at least one first set of equally spaced symbols, and a second pilot sequence at a second symbol rate higher than the first symbol rate, the second pilot sequence including at least one first set of equally spaced symbols and at least one second set of equally spaced symbols interleaved therewith, and includes a pilot sequence selected between the second pilot signal transmitted by the second transmitter is at least a first additional pilot sequence transmitted at the first symbol rate, the first additional pilot sequence including at least one first additional set of equally spaced symbols, and a second additional pilot sequence (S EG ) transmitted at a second symbol rate higher than the first symbol rate, the second additional pilot sequence (S EG ) including at least one first additional set of equally spaced symbols and at least one second additional set of equally spaced symbols interleaved therewith, the second additional pilot sequence (SEG ) and includes an additional pilot sequence selected therebetween, at least one first set of equally-spaced symbols represents at least one first code orthogonal to at least one first additional code represented by at least one first additional set of equally-spaced symbols, at least one second set of equally-spaced symbols represents at least one second code orthogonal to at least one second additional code represented by at least one second additional set of equally-spaced symbols, the receiver samples the received signal at a symbol rate that is either a first symbol rate or a second symbol rate, and in order to obtain information regarding the channel between the first transmitter and the receiver and information regarding the channel between the second transmitter and the receiver, a set of equally-spaced symbols and a pre-stored version of the additional set (S A , S C S E S G S AC S EG ) can both be correlated with the received signal.

[0024] When the receiver samples at the second symbol rate, at least, in order to obtain channel information regarding the channel between the first transmitter and the receiver, the received signal and, a pre-stored version of at least one first set of equally-spaced symbols, a pre-stored version of at least one second set of equally-spaced symbols, and a pre-stored version of at least one first set of equally-spaced symbols interleaved with a pre-stored version of at least one second set of equally-spaced symbols of which at least one and the correlation therebetween can be evaluated. When the receiver samples at the second symbol rate, at least, To obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, a pre-stored version of at least one first additional set of equally-spaced symbols, a pre-stored version of at least one second additional set of equally-spaced symbols, and a pre-stored version of at least one first additional set of equally-spaced symbols interleaved with a pre-stored version of at least one second additional set of equally-spaced symbols (S EG ) of at least one of can evaluate the correlation between.

[0025] When sampling at the first symbol rate, the receiver can, at least To obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, a pre-stored version of at least one first set of equally-spaced symbols, and a pre-stored version of at least one second set of equally-spaced symbols of at least one of can evaluate the correlation between. When sampling at the first symbol rate, the receiver can, at least To obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, a pre-stored version of at least one first additional set of equally-spaced symbols, and a pre-stored version of at least one second additional set of equally-spaced symbols of at least one of can evaluate the correlation between.

[0026] The receiver may be such that when a pre - stored version of at least one first code represented by at least one first set of equally - spaced symbols and a pre - stored version of at least one second code represented by at least one second set of equally - spaced symbols are interleaved with each other, they form a composite code orthogonal to an additional composite code that includes at least one additional code orthogonal to the at least one first code and a second additional code orthogonal to the at least one second code. As a result, within the additional composite code, the at least one first additional code and the at least one second additional code are interleaved with each other such that the positions of the entries of each first code and the entries of each orthogonal first additional code correspond. The composite code may be stored in a memory unit, and the receiver is configured to retrieve a code represented by a pre - stored version of at least one second code used according to the composite code. The receiver includes or can access a memory unit in which multiple pre - stored versions of codes are stored. The pre - stored versions of the codes are stored according to a format in which multiple codes are interleaved with other codes to form a composite code. As a result, the pre - stored version of the code selected for correlation evaluation is obtained from the selected position of the composite code.

[0027] For each code used for each set of equally - spaced symbols, the receiver can receive signaling from an adjuster indicating which composite code among a plurality of stored composite codes is selected, and which shift the selected interleaved codes have within the selected composite code to identify the set of equally - spaced entries within the selected composite code from which the selected sequence of symbols is obtained. The receiver can evaluate the correlation between multiple pre - stored versions of a set of equally - spaced symbols and thereby identify which set of symbols is used by each transmitter. The receiver may be a wireless receiver. The receiver may be an optical receiver. The receiver may be a radio frequency (RF) receiver. The receiver may be a mobile device. The receiver may be a fixed - location device. The receiver may be wired to a regulator.

[0028] According to one aspect, a method for defining pilot sequences transmitted simultaneously by a plurality of transmitters is provided. The method includes: defining a set of codes including a plurality of codes and a plurality of additional codes such that each code of the plurality of additional codes is orthogonal to a related code of the plurality of codes; combining each first code among the plurality of codes with a second code among the plurality of codes, and combining each first additional code among the plurality of additional codes with a second additional code among the plurality of additional codes; allocating the plurality of codes and signaling them to a first transmitter such that the first transmitter is configured to transmit a first pilot sequence having a set of equally - spaced symbols representing the first code at a first symbol rate and a second pilot sequence having a first set of equally - spaced symbols representing the first code and a second set of equally - spaced symbols representing the second code at a second symbol rate higher than the first symbol rate; allocating the plurality of additional codes and signaling them to a second transmitter such that the second transmitter is configured to transmit a first additional pilot sequence having a set of equally - spaced symbols representing the first code at a first symbol rate and a second pilot sequence having a first set of equally - spaced symbols representing the first code and a second set of equally - spaced symbols representing the second code interleaved therewith at a second symbol rate higher than the first symbol rate; including.

[0029] The plurality of codes can be interleaved with each other, thereby forming at least one composite code that is orthogonal to at least one composite code formed by interleaving at least one plurality of additional codes. The code may be a Gold+1 code. The method may be such that each code within a set of codes enjoys a "balanced property" such that, for each code within the set of codes, the number of entries having a first logical value is the same as the number of entries having a second logical value different from the first logical value. For each pilot signal transmitted by each transmitter, P pilot sequence slot positions may be defined such that each transmitter transmits P different selected pilot sequences, each at one of P pilot sequence slot positions. For each transmitter, each of the P different selected pilot sequences is obtained from at least V different codes, such that at least P*V possible combinations between the P pilot sequence slot positions and the at least V different codes are implied, and the at least P*V possible combinations are enumerated according to a predetermined order. As a result, the transmitter can receive signaling that selects P selected combinations that associate the P selected pilot sequences transmitted at each of the respective P pilot sequence slot positions.

[0030] The at least P*V possible combinations may be enumerated according to a combination index, and the combination index of each of the P selected combinations is provided within the signaled index. The method may be such that the signaled index encodes a number between 0 and P*V-1. At least V different stored pilot sequences may be enumerated from 0 to V-1, P pilot sequence slot positions are enumerated from 0 to P-1, and P selected combinations are obtained by performing an integer division between the signaled index and P or V, such that each position is associated with a combination obtained from the integer result of the integer division and the remainder of the integer division.

[0031] A method for transmitting a pilot signal including a pilot sequence may be provided, the pilot sequence including at least one first set of equally spaced symbols, and at least one second set of equally spaced symbols, wherein the symbols of at least one second set of equally spaced symbols are inserted between the symbols of at least one first set of equally spaced symbols, and including a plurality of symbols having The method defines at least one first set of equally spaced symbols such that each first set of equally spaced symbols represents a respective first code, and at least one second set of equally spaced symbols such that each second set of equally spaced symbols represents a respective second code and includes selecting each first code and each second code from a set of codes where each code of the set of codes is orthogonal to at least one other code of the set of codes. According to one aspect, a method for transmitting a pilot signal including a pilot sequence selected from a plurality of pilot sequences including at least a first pilot sequence and a second pilot sequence is provided, the first pilot sequence including a plurality of symbols of the first pilot sequence, The second pilot sequence includes the symbols of the first pilot sequence and further symbols of the second pilot sequence inserted between the symbols of the first pilot sequence, The method is, The symbols of the first pilot sequence include at least one first set of equally spaced symbols, each first set of equally spaced symbols representing a respective first code, and The symbols of the second pilot sequence include at least one second set of equally spaced symbols, each second set of equally spaced symbols representing a respective second code different from each first code including defining, The method includes selecting each first code and each second code from a set of codes in which each code of the set of codes is orthogonal to at least one other unselected code of the set of codes, The method includes transmitting the selected pilot sequence.

[0032] According to one aspect, a method is provided for adjusting a simultaneous pilot signal of different pilot sequences transmitted by a plurality of transmitters including at least one first transmitter and one second transmitter, The method is, assigning to the first transmitter a plurality of codes including at least one first code and at least one second code, the at least one first code and the at least one second code being codes of a set of codes, and assigning to the second transmitter a plurality of additional codes including at least one first additional code and at least one second additional code, the at least one first additional code and the at least one second additional code being codes of a set of codes, the at least one first additional code being orthogonal to the at least one first code, and the at least one second additional code being orthogonal to the at least one second code including assigning, The method includes, for each of a plurality of transmitters, selecting at least one symbol rate from a plurality of symbol rates including at least one first lower symbol rate and one second higher symbol rate, The method includes signaling to each transmitter a code assigned to that transmitter and signaling to each transmitter the selected symbol rate, whereby if a first symbol rate is selected for a first transmitter, the first transmitter transmits a first pilot sequence including a first set of equally spaced symbols, if a second symbol rate is selected for the first transmitter, the first transmitter transmits a second pilot sequence including at least one first set of equally spaced symbols and at least one second set of equally spaced symbols interleaved with at least one first set of equally spaced symbols, if a first symbol rate is selected for a second transmitter, the second transmitter transmits a first additional pilot sequence including at least one first additional set of equally spaced symbols, if a second symbol rate is selected for the second transmitter, the second transmitter transmits a second additional pilot sequence including at least one first additional set of equally spaced symbols and at least one second additional set of equally spaced symbols interleaved with at least one first additional set of equally spaced symbols.

[0033] According to one aspect, a method is provided for obtaining phase information of a pilot signal from a pilot sequence within the pilot signal, the pilot sequence including a plurality of sets of equally spaced symbols interleaved with each other, the method including evaluating a correlation between the pilot sequence and a pre-stored version of the plurality of sets of equally spaced symbols, thereby determining a set of codes having the highest correlation with the pilot sequence to obtain phase information from the determination of the set of codes having the highest correlation with the pilot sequence. According to one aspect, a method for evaluating channel information from a received signal received from a plurality of pilot signals transmitted simultaneously by a plurality of transmitters is provided. The plurality of transmitters includes at least a first transmitter and a second transmitter, and as a result, The first pilot signal transmitted by the first transmitter is at least A first pilot sequence at a first symbol rate, the first pilot sequence including at least one first set of equally spaced symbols, the first pilot sequence, and A second pilot sequence at a second symbol rate higher than the first symbol rate, the second pilot sequence including at least one first set of equally spaced symbols and at least one second set of equally spaced symbols interleaved therewith, the second pilot sequence Including a pilot sequence selected between The second pilot signal transmitted by the second transmitter is at least A first additional pilot sequence transmitted at the first symbol rate, the first additional pilot sequence including at least one first additional set of equally spaced symbols, the first additional pilot sequence, and A second additional pilot sequence (S EG ) transmitted at a second symbol rate higher than the first symbol rate, the second additional pilot sequence (S EG ) including at least one first additional set of equally spaced symbols and at least one second additional set of equally spaced symbols interleaved therewith, the second additional pilot sequence (S EG ) and Including an additional pilot sequence selected between At least one first set of equally spaced symbols represents at least one first code orthogonal to at least one first additional code represented by at least one first additional set of equally spaced symbols, At least one second set of equally spaced symbols represents at least one second code that is orthogonal to at least one second additional code represented by at least one second additional set of equally spaced symbols. The method includes sampling a received signal at a symbol rate that is either a first symbol rate or a second symbol rate, and correlating the received signal with both a stored version of a set of equally spaced symbols and an additional set to obtain information regarding a channel between a first transmitter and the receiver and information regarding a channel between a second transmitter and the receiver.

[0034] There may be provided a non-transitory storage unit storing instructions that, when executed by a processor, cause the processor to control the method according to the previous aspect. There may be provided a non-transitory storage unit storing instructions that, when executed by a processor, cause the processor to execute the method according to the previous or subsequent aspect. The receiver (and any related method) may also be configured to receive a signal to be then evaluated (the method includes a step of receiving a signal, e.g., a received signal).

[0035] The transmitter (and any related method) may also be configured to transmit a pilot signal (and a pilot sequence) (the method includes a step of transmitting a signal, e.g., a pilot signal). The regulator (and any related method) may also signal a selected pilot signal (and a pilot sequence) (the method includes a step of signaling an assigned code, a selected symbol rate), and may be configured to transmit a beacon when a beacon is provided.

[0036] The pilot signal may include a pilot sequence, and the pilot sequence at least one first set of equally spaced symbols, and At least one second set of equally spaced symbols, wherein the symbols of at least one second set of equally spaced symbols are inserted between the symbols of at least one first set of equally spaced symbols, and comprising a plurality of symbols having select at least one first set of equally spaced symbols such that each first set of equally spaced symbols represents a respective first code, and select at least one second set of equally spaced symbols such that each second set of equally spaced symbols represents a respective second code is possible. Each first code and each second code may be selected from a set of codes where each code of the set of codes is orthogonal to at least one other code of the set of codes. The same technique of transmitting a sequence using a code orthogonal to the code transmitted by a transmitter may be implemented in another transmitter.

Brief Description of the Drawings

[0037]

Fig. 1a

Fig. 1b

Fig. 2

Fig. 3

Fig. 4a

Fig. 4b

Fig. 5

Fig. 6

Fig. 7

Modes for Carrying Out the Invention

[0038] Example Hereinafter, for example, an optical sequence (e.g., an optical pilot signal) for obtaining a channel impulse response or other information regarding an optical channel (e.g., phase), or more generally, a wireless pilot sequence, e.g., a radio frequency (RF) pilot sequence (e.g., an RF signal) for obtaining a channel impulse response or other information regarding an optical channel, or other wireless sequences (e.g., ultrasonic waves) will be mainly referred to. The modulation may be, for example, PAM-2. Each symbol of the pilot sequence may be represented by the emission of light (or another form of wave) at a predetermined wavelength (or wavelength range) during a predetermined time slot when it is 1, or by the absence of emission during a predetermined time slot when it is 0, and vice versa. The state of the signal may change for each time slot into which the time reference is subdivided, and the time slots have the same time length. Here, it is generally exemplified that a symbol can be a single bit (i.e., either a first binary value or a second binary value different from the first binary value is encoded), but in some other modulations, a symbol can encode two or more bits (e.g., according to a selected specific modulation and the constellation defined therefrom), for example, PAM-4 encodes 2 bits for each time slot. One single symbol (or a plurality of consecutive symbols) may be transmitted for each single continuous and non-interrupted time slot. Depending on the state of the wave in each time slot (e.g., emission vs. non-emission in PAM-2), one single symbol may be transmitted, and the single symbol is one single bit. Alternatively, in a plurality of directly consecutive time slots, one symbol may be transmitted, and the single symbol is a plurality of bits (one bit for each of the consecutive time slots). In some examples, a plurality of directly consecutive bits may form one single symbol. Generally, the following examples refer to time-domain transmissions in which different symbols are transmitted within different time slots.

[0039] The pilot sequence will be described below. The pilot sequence can be a known sequence transmitted from a transmitter (e.g., an optical front end) to a receiver (e.g., a receiver), such that as a result, the receiver can derive the impulse response and / or other characteristics of the optical channel from the reception of the pilot sequence. The pilot sequence may be composed of a plurality of symbols (e.g., bits) within a sequence that can be predefined according to a specific modulation (e.g., PAM-2). Each group of symbols (e.g., bits) of the pilot sequence can also be formed by discontinuous symbols and can be a subsequence (including one or more sets of equally spaced symbols). There may be one or more predefined subsequences for each pilot sequence, and the pilot sequence may be composed of at least one subsequence or a plurality of different subsequences (or sets of equally spaced symbols) interleaved with each other. When different subsequences (or sets of equally spaced symbols) are interleaved within the same pilot sequence, in some examples, a symbol is a symbol of the first subsequence (or set of equally spaced symbols), and the immediately preceding symbol and / or the immediately following symbol are symbols of the second subsequence (or a different set of equally spaced symbols). The subsequence may also include one or more sets of equally spaced symbols. When different subsequences are interleaved within the same pilot sequence, in some examples, each of the two different interleaved subsequences may be formed by a respective set of equally spaced symbols (in the example, the different sets of equally spaced symbols may follow a time offset so that they do not overlap). The code may be represented by a plurality of symbols (e.g., bits) transmitted along a time series.The code may be represented by a set of multiple sub - sequences or equally - spaced symbols, or (for example, when a sub - sequence contains multiple symbols or bits) by the sub - sequence itself, or a sub - sequence (or a different set of equally - spaced symbols) may represent multiple codes. Each code used for a particular pilot sequence may be selected from a set of pre - defined codes. Specifically, a set of orthogonal codes may be used (the set of codes may have orthogonal codes for each code). When a transmitter transmits a pilot sequence, each code used is orthogonal to at least one code that is not used, because it is used by another transmitter transmitting simultaneously. Generally, the first code used by a transmitter for a pilot sequence is also orthogonal to the second code used by the same transmitter for the same pilot sequence. In that case, the set of codes is recognized to have additional unused first codes orthogonal to the first code used and additional unused second codes orthogonal to the second code used (as a result, an additional transmitter can simultaneously transmit an additional pilot sequence with additional codes orthogonal to the codes used by the transmitter). Each pilot sequence can represent one code or multiple codes that can be interleaved with each other. One sub - sequence can represent multiple codes interleaved with each other. Each set of equally - spaced symbols may be associated with one code. The pilot signal transmitted by a transmitter may contain multiple different pilot sequences (e.g., eight pilot sequences), which are also called “variants” and are repeated within subsequent pilot sequence slots (in the example, all different variants are transmitted either at a higher symbol rate than the second or at a lower symbol rate than the first).

[0040] This example refers to a pilot sequence that includes a set of equally spaced symbols. For example, the pilot sequence may include at least one (i.e., one or more) set of equally spaced symbols. Each set of equally spaced symbols may include an ordered series of symbols that are transmitted at successive time instants (time slots) over a certain period of time. If A1 is the first symbol of a set of equally spaced symbols and A2 and A3 are subsequent symbols within the set of equally spaced symbols, the transmission of A2 occurs after a time distance Δ t 12 has elapsed since the transmission of A1, and the transmission of A3 occurs after the same time distance Δ t 12 has elapsed since the transmission of A2. Symbols A1, A2, A3, etc. may be binary values. The values of A1, A2, A3, etc. may be determined by their relative positions within the sequence. The pilot sequence can include multiple sets of symbols in the sense that, in addition to the succession of A1, A2, A3, etc., different successions (different sets of equally spaced symbols B1, B2, B3, etc.) are also defined. It can be, for example, that within the pilot sequence, symbols B1, B2, B3, etc. are inserted one by one between symbols A1, A2, A3, etc. of other sets of equally spaced codes. Also, symbols B1, B2, B3, etc. have a distance Δ t 12It can only be equally spaced. Therefore, within different time slots, there may be symbols of equally spaced slots within the same pilot sequence, thereby forming pilot sequences A1, B1, A2, B2, A3, B3, etc. In some cases, in addition to the symbols A1, A2, A3, etc. of the first sequence (or in the case of the symbols A1, B1, A2, B2, A3, B3 of the second sequence), symbols C1, C2, C3 (or B1, D1, B2, D2, B3, D3, B4, D4) of another sequence are also inserted between the symbols A1, A2, A3, etc. of the first sequence (or A1, B1, A2, B2, A3, B3, etc.) so that a second pilot sequence is generated. Even the symbols C1, C2, C3 (or B1, D1, B2, D2, B3, D3, B4, D4) of the second pilot sequence are a set of equally spaced symbols. As a result, the transmission of B2 is carried out after a time distance Δ t 12 has elapsed since the transmission of B1, and the transmission of B3 is carried out after the same time distance Δ t 12 has elapsed since the transmission of B2 (and / or the transmission of D2 is carried out after a time distance Δ t 12 has elapsed since the transmission of D1, and the transmission of D3 is carried out after the same time distance Δ t 12 has elapsed since the transmission of D2). The above techniques may be generalized for multiple sets of symbols, multiple symbols for each set of symbols, multiple pilot sequences, etc.

[0041] Note that the symbol and the pilot sequence can represent code. More generally, each symbol transmitted may be understood to represent the corresponding entry of a particular code. As a result, each set of equally spaced symbols can represent the corresponding code. The code is here conjectured to be a series of entries at positions corresponding to the positions of the entries in each set of equally spaced codes. Each entry of the code may be uniquely represented by a symbol and / or each code may be represented by one or more sets of equally spaced codes. Since the code itself does not actually take into account the time duration of the particular slot in which each symbol is transmitted, the difference between the code and the corresponding set of equally spaced symbols can be conjectured. Thus, the code is generally transparent to the symbol rate in the sense that when the code is stored in a memory unit, it does not carry an indication regarding the time duration of the time slot in which the corresponding symbol is transmitted. Another important concept associated with the code is the orthogonality of the code in the sense that it is possible for the code to have an orthogonal code associated with it. For example, TIFF0007717967000001.tif843 where a = (a1, a2, a3,... a N ) and b = (b1, b2, b3,... b N ) are two codes orthogonal to each other, both having entries of dimension N, each entry a i and b iEach value is, for example, either +1 or -1). In general, when two transmitters simultaneously transmit different sequences obtained from orthogonal codes, the mutual interference is minimized (each symbol of each pilot sequence may be transmitted during time slots corresponding to specific positions of the entries in the code corresponding to the transmitted sequence). Each code can have a dimension (e.g., N), which can be the number of its entries, which corresponds to the number of symbols in a set of symbols. In particular, in general, it is possible to interleave different codes in the same way that symbols of different sets of codes are interleaved with each other to form a pilot sequence. More generally, each pilot sequence may model (or be generated from) a plurality of codes interleaved with each other. Hereinafter, when it is referred to orthogonality, it is clear that it can also be applied to pilot sequences and sets of equally spaced symbols, since it refers to the orthogonality between codes represented by a pilot sequence or a set of equally spaced symbols. Also, the fact that some sequences are stored in some memory units may be understood to be the same as the codes being stored in the memory units. Also, it is clear that codes (e.g., obtained by accessing a memory unit) are used to generate sets of equally spaced symbols and pilot sequences.

[0042] In this specification, the notations used to indicate codes and entries are often the same as those used to indicate sets of equally spaced symbols and symbols for the sake of brevity. Note that most of the examples here refer to exemplifying codes of dimension N = 4 for the sake of simplification, although the codes used usually have dimensions where N >> 4, e.g., N > 15, i.e., N = 64, N = 128, N = 256, N = 516, N = 1024, N = 2048, etc. (N can generally be a power of 2 of an integer obtained by raising 2 to an integer exponent). Using the concept of orthogonal codes, the inventors understand that it is possible to group the codes intelligently so that it is easy for the transmitter to select a code that is orthogonal to another code (or an interleaved code such as a composite code formed by interleaving a plurality of codes), and thus, two different transmitters can transmit pilot sequences representing codes that are orthogonal to each other, thereby minimizing mutual interference. Specifically, it is possible to define a set of codes as follows.

[0043] 1) The first transmitter is assigned a first code (e.g., A1A2A3A4), and the second transmitter is assigned a first additional code (e.g., E1E2E3E4) that is orthogonal to the first code (A1A2A3A4). 2) The first transmitter is assigned a second code (e.g., C1C2C3C4), and the second transmitter is assigned a second additional code (e.g., G1G2G3G4) that is orthogonal to the second code (C1C2C3C4). 3) When interleaved with each other, the first code (A1A2A3A4) and the second code (C1C2C3C4) form another code (A1C1A2C2A3C3A4C4) that is orthogonal to another code (E1G1E2G2E3G3E4G4) formed by interleaving the first additional code (E1E2E3E4) and the second additional code (G1G2G3G4). 4) This procedure can be repeated to form multiple layers of composite codes from the initial codes.

[0044] In this example, · When the first transmitter transmits a first pilot sequence having a reduced number of symbols (e.g., at a lower symbol rate, e.g., having N = 4 symbols for simplicity), the first transmitter transmits the sequence based on the first code (A1A2A3A4), and at the same time, the second transmitter · To minimize the interference between the first pilot sequence (A1A2A3A4) and the first additional pilot sequence (E1E2E3E4), based on the first additional code (E1E2E3E4), can a first additional pilot sequence with a reduced number of symbols (at the same lower symbol rate, e.g., having N = 4 symbols) be transmitted, or · Based on an additional composite code (E1G1E2G2E3G3E4G4) formed by interleaving the first additional code (E1E2E3E4) with a second additional code (G1G2G3G4), a second additional pilot sequence with an increased number of symbols (at an increased, e.g., doubled symbol rate, e.g., having N = 8 symbols) can be transmitted, thereby also minimizing the interference between the first pilot sequence (A1A2A3A4) and the second additional pilot sequence (E1G1E2G2E3G3E4G4). · When the first transmitter transmits a second pilot sequence with an increased number of symbols (e.g., at a higher symbol rate, e.g., for simplicity having N = 8 symbols), the first transmitter transmits the sequence based on a composite code (A1C1A2C2A3C3A4C4) formed by the first code (A1A2A3A4) and the second code (C1C2C3C4), and at the same time, the second transmitter · To minimize the interference between the second pilot sequence (A1C1A2C2A3C3A4C4) and the first additional pilot sequence (E1E2E3E4), based on the first additional code (E1E2E3E4), can a first additional pilot sequence with a reduced number of symbols (at a symbol rate lower than the symbol rate being transmitted by the first transmitter, e.g., having N = 4 symbols) be transmitted, or · Based on the additional composite code (E1G1E2G2E3G3E4G4) formed by interleaving the first additional code (E1E2E3E4) with the second additional code (G1G2G3G4), a second additional pilot sequence having an increased number of symbols (at the same increased symbol rate as the symbol rate transmitted by the first transmitter, e.g., having N = 8 symbols) can be transmitted, thereby also minimizing the interference between the second pilot sequence (A1C1A2C2A3C3A4C4) and the second additional pilot sequence (E1G1E2G2E3G3E4G4).

[0045] Basically, the first and second transmitters transmit different sequences mainly having codes orthogonal to each other between the same pilot sequence slots. Generally, when it is selected whether to transmit sequences transmitted within the same pilot sequence slot (e.g., between a longer sequence and a shorter sequence), the symbol rate is also selected. In this case, for example, the time length of each time slot of the second high-symbol-rate pilot sequence decreases by the same ratio as the symbol rate of the second pilot sequence increases relative to the symbol rate of the first pilot sequence, relative to the time length of each time slot of the first low-symbol-rate pilot sequence. The ratio can be an integer that is a power of 2 raised by an integer exponent (such as 2, 4, 8, 16, 32, etc.).

[0046] In the example of the transmitter, it is not necessary to memorize all possible codes used. For example, the first transmitter does not necessarily have to memorize the first additional code and the second additional code since they are used by the second transmitter. The same applies to the second transmitter, which also does not need to memorize the first code and the additional codes since they are used by the first transmitter. In some examples, (e.g., in the initialization process) the first and second codes are assigned to the first transmitter and the first and second additional codes are assigned to the second transmitter, for example, by an adjuster. In some examples, at least some of the codes used are pre-stored in a memory unit, but additionally or alternatively, at least some of the codes used are provided to each transmitter by an adjuster (e.g., during an initialization procedure).

[0047] In some examples, the codes used by each transmitter may be stored in an interleaved fashion to generate a composite code. In particular, the first transmitter may store therein the first code (A1A2A3A4) and the second code (C1C2C3C4) in an interleaved fashion, in the sense that the code may be stored in the form of A1C1A2C2A3C3A4C4. Similarly, the second transmitter may store therein the first additional code (E1E2E3E4) and the second additional code (G1G2G3G4) in an interleaved fashion, whereby an additional composite code in the form of E1G1E2G2E3G3E4G4 is stored. In these cases, a highly advantageous configuration of the storage device is obtained, and the composite codes A1C1A2C2A3C3A4C4 and the additional composite code E1G1E2G2E3G3E4G4 may also be used to generate a second higher symbol rate pilot sequence or an additional second higher symbol rate pilot sequence. Thus, the storage space required for each transmitter is reduced (and the signaling payload is reduced if an initialization procedure is performed in which the codes are signaled from the regulator to the transmitter). In the case of the first transmitter, it is only necessary to obtain the first code (A1A2A3A4) and / or the second code (C1C2C3C4) from the stored composite code A1C1A2C2A3C3A4C4 by selecting the entries (A1, A2, A3, A4 and / or C1, C2, C3, C4) from the composite code A1C1A2C2A3C3A4C4 that are the entries of the codes to be used. The same applies to the second transmitter.

[0048] In examples, · for at least one first code, the entry of each first code is arranged at equally spaced positions of the composite code, · for at least one second code, the entry of each second code is arranged at equally spaced positions of the composite code. Thus, when the first pilot sequence is selected, the symbols of each first sequence are obtained from the entries of each first code, and when the second pilot sequence is selected, the symbols of each first sequence are obtained from the entries of the first code, and the symbols of each second sequence are obtained from the entries of the second code.

[0049] In general, a composite code is orthogonal to an additional composite code that includes at least one additional code orthogonal to at least one first code and at least one second additional code orthogonal to at least the second code. As a result, within at least one additional composite code, at least one first additional code and at least one second additional code are each interleaved such that the entries of each first additional code are in positions corresponding to the entries of the respective orthogonal first additional code within the composite code, and the entries of each second additional code are in positions corresponding to the entries of the respective orthogonal second additional code within the composite code.

[0050] In the examples below and above, it may be irrelevant whether the first and second transmitters are mobile devices (e.g., user equipment) or fixed devices (e.g., part of a base station, e.g., an adjuster-side device, or a relay device). In FIG. 4a, the first and second transmitters are fixed devices 320a and 320b, respectively. In FIG. 4b, the first and second transmitters are mobile devices 350a and 350b, respectively. FIG. 2 shows the difference between the code assigned to the first transmitter (e.g., 320a, 350a) and the additional code assigned to the second transmitter (e.g., 320b, 350b). In FIGS. 1a, 1b, 4a, and 4b, the storage unit 100 that stores the code is referenced. Here, the storage unit 100a of the first transmitter 350a stores the first and / or second code (e.g., in the form of interleaved composite code S ABCD and the storage unit 100b of the second transmitter 350b stores the additional composite code S (e.g., in the form of interleaved EFGHIt is distinguished from the storage unit 100 that stores the first and / or second additional codes in the form of). The storage unit 100 (100a, 100b) may lack the transmitters 320a, 320b when the first or second transmitter is a fixed device (e.g., on the base station side) since the storage unit 100 can be in the adjustment unit.

[0051] Therefore, it is possible to generate a pilot sequence according to one of the following rules. First, the wireless transmitter can select one pilot sequence generated and transmitted from among a plurality of pilot sequences. Specifically, the pilot sequence may be selected between a first pilot sequence (which can be transmitted at a first reduced data rate) and a second pilot sequence (which can be a second full data rate, e.g., twice the first data rate). The first pilot sequence that can be selected includes a plurality of symbols. The second pilot sequence may include the symbols of the first pilot sequence and additional symbols (not symbols of the first pilot sequence) that can be inserted (e.g., interleaved) between the symbols of the first pilot sequence.

[0052] Some examples are provided below. First example: The transmitter (e.g., the first transmitter) selects the pilot sequence to be transmitted from the following (among the following). 1) The first pilot sequence S A =A1A2A3A4 It is the first code: S A =A1A2A3A4 represents the subsequence: A1A2A3A4 (a set of equally spaced symbols) formed by. 2) The second pilot sequence S AC =A1C1A2C2A3C3A4C4 It is two subsequences: One second code: S AA1, A2, A3, A4 representing =A1A2A3A4 (these symbols form a set of equally spaced symbols) One second code: S C C1, C2, C3, C4 representing =C1C2C3C4 (these symbols form a set of equally spaced symbols) is formed by

[0053] The second pilot sequence S AC The symbols C1, C2, C3, C4 of A are inserted between and interleaved with the unique symbols A1, A2, A3, A4 of the first pilot sequence S In other words, the transmitter can determine whether to transmit the first pilot sequence S A or the second pilot sequence S AC The first pilot sequence S A is here considered to be formed by four symbols (e.g., 4 bits), and each of A1, A2, A3, and A4 is a symbol (e.g., a bit). Thus, the first pilot sequence S A is formed by a subsequence of four symbols transmitted one after another

[0054] When the transmitter (e.g., the first transmitter) determines to transmit the second pilot sequence, the symbol A1 、ANot only transmit sequences of A2, A3, A4, but also transmit symbols C1, C2, C3, C4 interleaved with them. In this case, there are two sub-sequences. The first sub-sequence is formed by symbols A1, A2, A3, A4, which is also a set of equally spaced symbols in the sense that they are transmitted one after another at the same relative time distance. The second sub-sequence is formed by symbols C1, C2, C3, C4, which is also a set of equally spaced symbols in the sense that they are transmitted at the same time distance. In particular, when the second pilot sequence is selected, when it is transmitted, it is composed of the sequence A1, C1, A2, C2, A3, C3, A4, C4. In this case, each symbol of the pilot sequence S AC is taken from the first sub-sequence, and the symbol immediately before and the symbol immediately after are taken from different second sub-sequences. When each symbol of a particular sub-sequence is transmitted, the amount of time for transmitting further symbols of the same sequence is constant. Therefore, the symbols of the same sub-sequence are also equally spaced.

[0055] Second example: The transmitter (e.g., the first transmitter) selects the pilot sequence to be transmitted from the following (among the following). 1) The first pilot sequence S A = A1A2A3A4 which represents the first code: S A = A1A2A3A4 is a sub-sequence: A1, A2, A3, A4 (a set of equally spaced symbols) formed by. 2) Sub-sequences: B1C1D1, B2C2D2, B3C3D3, B4C4D4 Three sets of equally spaced symbols: (code: S B = B1B2B3B4 represents) B1, B2, B3, B4 (code: S C = C1C2C3C4 represents) C1, C2, C3, C4 (Code: S D = representing D1D2D3D4) D1, D2, D3, D4 Second code: S A = representing A1A2A3A4) A1, A2, A3, A4 (a set of equally spaced symbols) The second pilot sequence S formed by ABCD = A1B1C1D1A2B2C2D2A3B3C3D3A4B4C4D4

[0056] Second pilot sequence S ABCD The subsequences of the unique symbols B1C1D1, B2C2D2, B3C3D3, B4C4D4 of the second pilot sequence S are interleaved with the subsequences of the unique symbols A1, A2, A3, A4 of the first pilot sequence S A . That is, it is possible to select between the first pilot sequence S In other words, the first pilot sequence S A and the second pilot sequence S ABCD . When the first pilot sequence S A is selected, the transmitter can transmit as in the first example (see above). Second sequence S ABCD is selected, the second pilot sequence may be considered to be formed by two subsequences. The first subsequence of symbols may be B1C1D1, B2C2D2, B3C3D3, B4C4D4, which is then three sets of equally spaced symbols: (Code: S B representing) B1, B2, B3, B4 (Code: S C representing) C1, C2, C3, C4 (Code: S D representing) D1, D2, D3, D4 and may be considered to be composed of . Also in this case, the symbols (e.g., bits) of each set of equally spaced symbols are transmitted at a constant time distance. The second pilot sequence S ABCDThe second sequence that is configured can be subsequences A1, A2, A3, A4, which are subsequences of the first pilot sequence.

[0057] Third example: The transmitter (e.g., the first transmitter) selects a pilot sequence to be transmitted during the following. 1) Subsequences: A1, C1, A2, C2, A3, C3, A4, C4 Two sets of equally spaced symbols: First code: S A = A1, A2, A3, A4 representing A1A2A3A4 First code: S C = C1, C2, C3, C4 representing C1C2C3C4 The first pilot sequence S formed by AC = A1C1A2C2A3C3A4C4 2) Subsequences: A1, C1, A2, C2, A3, C3, A4, C4 Two sets of equally spaced symbols: Second code: S A = A1, A2, A3, A4 representing A1A2A3A4 Second code: S C = C1, C2, C3, C4 representing C1C2C3C4 B1, D1, B2, D2, B3, D3, B4, D4 Two sets of equally spaced symbols: Second code: S B = B1, B2, B3, B4 representing B1B2B3B4 Second code: S D = D1, D2, D3, D4 representing D1D2D3D4 The second pilot sequence S formed by ABCD = A1B1C1D1A2B2C2D2A3B3C3D3A4B4C4D4

[0058] The second pilot sequence S ABCDThe sub-sequences B1, D1, B2, D2, B3, D3, B4, D4 of the symbols are interleaved with the sub-sequences A1, C1, A2, C2, A3, C3, A4, C4 of the first pilot sequence S AC That is, when the first pilot sequence S is selected, the sub-sequences A1, C1, A2, C2, A3, C3, A4, C4 are transmitted. The sub-sequences may be considered to be composed of two sets of equally spaced symbols, i.e., A1, A2, A3, A4 (representing code S AC ) and C1, C2, C3, C4 (representing code S A ). In this case, each symbol of each set of equally spaced symbols is transmitted after a certain amount of time from the symbol immediately preceding the same set of equally spaced symbols and the symbol succeeding the same set of equally spaced symbols. C When the second pilot sequence S ABCD is selected, the sequence of symbols A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, B4, C4, D4 is transmitted. The second pilot sequence S ABCD may be considered to be composed of two sub-sequences interleaved with each other. The first sub-sequence is the sub-sequence A1, C1, A2, C2, A3, C3, A4, C4 of the first pilot sequence. (The second sub-sequence, which is the unique sub-sequence of the second pilot sequence S ABCD ) is B1, D1, B2, D2, B3, D3, B4, D4. In particular, the second sub-sequence (i.e., the unique sub-sequence of the second pilot sequence) may be considered to be formed by two sets of equally spaced symbols: B1, B2, B3, B4 (representing code S B ) and D1, D2, D3, D4 (representing code S D ). Even in this case, the sub-sequences are interleaved with each other, and the sets of equally spaced symbols are also interleaved with each other in the same sub-sequence.

[0059] ​The above example can be generalized. The code need not, for example, have only 4 symbols (e.g., there may be 1024 symbols, or generally another number of symbols that is 2 raised to an integer exponent). Further, the code may be selected from a set of orthogonal codes. A codebook (e.g., orthogonal codes) may be stored in a memory unit so that a transmitter can determine the most appropriate code. The bit rate (or more generally, symbol rate or data rate) for transmitting the first pilot sequence may be different from the bit rate (symbol rate or data rate) for transmitting the second pilot sequence. Generally speaking, the second pilot sequence may be transmitted at a higher data rate than the data rate at which the first pilot sequence is transmitted. For example, in the first example above, the second pilot sequence S AC may be transmitted at a bit rate (symbol rate or data rate) that is twice the data rate at which the first pilot sequence is transmitted. In the second example, the second pilot sequence S ABCD is transmitted at a bit rate (symbol rate or data rate) that is four times the bit rate (symbol rate or data rate) at which the first pilot sequence is transmitted. In the third example, the second pilot sequence S ABCD is transmitted at a bit rate (symbol rate or data rate) that is twice the bit rate (symbol rate or data rate) at which the first pilot sequence S AC is transmitted.

[0060] An example is provided by FIG. 1a. Here, the memory unit 100 stores (or is otherwise configured to use) a plurality of codes such as S A 、S C 、S B 、S D 、S AC 、S BD 、S ABCD . In the first example above, the transmitter uses the pilot sequence S ATransmit the (first pilot sequence) and select between transmitting the pilot sequence S AC and the (second pilot sequence). As shown in FIG. 1a, the time distance between the transmissions of each symbol A1, A2, A3, A4 is constant. On the other hand, when the pilot sequence S AC is transmitted, the transmitter must also transmit the symbols C1, C2, C3, C4 of the code S A interleaved with the code S C , so the bit rate (symbol rate) is doubled (as explained above, here two sets of equally spaced symbols A1, A2, A3, A4 and C1, C2, C3, C4 are transmitted. In the second example above, the pilot sequence S ABCD that serves as the (second pilot sequence) has a symbol rate that is 4 times the symbol rate of the transmission of the pilot signal S A that serves as the (first pilot sequence). In the third example, the second pilot sequence S ABCD that serves as the (second pilot sequence) is transmitted at a symbol rate that is twice the symbol rate at which the pilot sequence S AC that serves as the (first pilot sequence) is transmitted. The example of FIG. 1a is repeated in FIG. 1b, which shows an additional pilot sequence that can be transmitted (or assigned) by a second transmitter.

[0061] FIG. 2 shows a method of generating a pilot sequence. In the example, the first sequence can only be obtained from the code S A instead of S B (for example, the first pilot sequence is composed of a set of B1, B2, B3, B4 at the first data rate), and the second pilot sequence can be S BD (for example, the codes S B , S Dformed by interleaving to form the sequences B1, D1, B2, D2, B3, D3, B4, D4, and thus the pilot sequence S BD constitutes). In other examples, S A 、S AC 、S ABCD are only used, and S B 、S C 、S D 、S BD etc. may be discarded for the purpose of generating the pilot sequence.

[0062] It is important to note that a subsequence or symbol or set of equally spaced symbols can be obtained from a codebook (dictionary) of pre - defined codes (e.g., orthogonal codes). The first transmitter, for example, (to transmit one possible pilot sequence which could be S A 、S C 、S B 、S D 、S AC 、S BD 、S ABCD ) can utilize the codes S A 、S C 、S B 、S D . However, the second transmitter can utilize a pilot sequence generated from other codes (e.g., S E 、S G 、S F 、S H 、S EG 、S FH 、and S EFGH ) selected from among S E 、S G 、S F 、S H ). Thus, if the codes are orthogonal (e.g., orthogonal to each other), the interference between the pilot sequences transmitted by two transmitters is minimized. Specifically, at least the code S A used by the first transmitter and the code S E used by the second transmitter may be defined as being orthogonal to each other. The code S A used by the first transmitter and the code S E used by the second transmitter may be defined as being orthogonal to each other. The code S A used by the first transmitter and the code S E used by the second transmitter may be defined as being orthogonal to each other. The code S A used by the first transmitter and the code S E used by the second transmitter may be defined as being orthogonal to each other. The code SC and the code S used by the second transmitter G may be stated to be orthogonal to each other. In particular, S A is orthogonal to S E and S C is orthogonal to S G then S AC is also orthogonal to S EG . Thus, if the first pilot sequence transmitted by the first transmitter is S A and the second pilot sequence transmitted by the first transmitter is S AC , then the first pilot sequence S E transmitted by the second transmitter is orthogonal to both the first pilot sequence S A and the second pilot sequence S AC transmitted by the first transmitter, and the second pilot sequence S EG transmitted by the second transmitter is orthogonal to both the first pilot sequence S A transmitted by the first transmitter and the second pilot sequence S AC transmitted by the first transmitter.

[0063] In some examples, the S B used by the first transmitter and the S F used by the second transmitter may be orthogonal to each other. Similarly, the S D used by the first transmitter may be orthogonal to the S H used by the second transmitter. Thus, any sequence (S A , S C , S D , S AC , S BD , S ABCD ) transmitted by the first transmitter is orthogonal to any pilot sequence (S E , S G , S F , S H , S EG , S FH that may be transmitted by the second transmitter.FGH ) results in being orthogonal. Therefore, it is possible to minimize the interference between two different transmitters that transmit those pilot sequences simultaneously. Thus, in a set of transmitters, the first transmitter may be assigned only from a group of codes (e.g., S A , S C , S D , S AC , S BD , S ABCD ), and the second transmitter may be assigned from a different group of codes (e.g., S E , S G , S F , S H , S EG , S FH , S EFGH ), which is particularly advantageous when each of the codes assigned to the first transmitter is orthogonal to each of the codes assigned to the second transmitter (or at least the codes transmitted simultaneously). Thus, each transmitter can utilize only a unique subset of orthogonal codes from a common set of orthogonal codes, and as a result, different transmitters transmit with different orthogonal codes.

[0064] In some examples, which set of codes (or subset of codes) is used for each transmitter is predefined. Basically, a ranking among the codes may be defined. For example, at a specific symbol rate, only one specific code is used (e.g., S A can be established in advance, S C , S B , S D is not used by the first transmitter, S E is used by the second transmitter, but S G , S F , S H , S EG , S FH , S EFGH is not used by the second transmitter), and at a different symbol rate (e.g., at a second symbol rate higher than the previous rate), a different specific code (e.g., S ACand S by the second transmitter EG ) may be established in advance to be used only. Therefore, in that case, the selection is, for the first transmitter (at the first lower symbol rate), the pilot sequence S A to transmit, and (at twice the symbol rate of the second) S AC to transmit, only between (similarly, for the second transmitter, between S G and S EG ). This is the case when the decision is between the first symbol rate and a symbol rate four times larger (for example, when deciding between transmitting the pilot sequence S A or the second pilot sequence S ABCD for the first transmitter, and transmitting S E and S EFGH for the second transmitter). Therefore, in some examples, the codes S C , S B , S BD and / or (for the second transmitter) S G , S F , S H , S FH are not used in that way to be a particular pilot sequence, although they are used to generate the pilot sequence by interleaving any of those codes with the codes S A , S AC , S ABCD , S E , S EG , S EFGH .

[0065] In an example, the selection of the symbol rate is performed by the transmitter based on its capabilities and / or state. For example, if the supply storage level is lower than a predetermined threshold, the transmitter can decide to transmit the first pilot sequence (at a lower symbol rate) instead of transmitting a second pilot signal (at a second, higher symbol rate). In other cases, the symbol rate (and also the selection between the first pilot sequence and the second pilot sequence) may be signaled, for example, by a master device. The request of the master device may be made, for example, based on the energy supply of the transmitter or receiver falling below a minimum threshold.

[0066] In other cases, the decision between the first pilot sequence and the second pilot sequence (and between their respective symbol rates) may be made based on the physical capabilities of the device. For example, if it is not physically possible for the receiver to receive and / or analyze a pilot sequence at the second, higher symbol rate, it may be preferable to transmit the first pilot sequence at the first, lower symbol rate. Even in this case, the decision may be made based on a command signaled by the master device.

[0067] Also, as will be described later, the transmitter may be a mobile device or a fixed device. The transmitter can be a client device connected to at least one receiver of a master device (especially when it is a mobile device) (which can generally be a fixed device). On the other hand, the transmitter can alternatively be a fixed device that is a device associated with (or included in) the master device. Generally speaking, it can be a central unit that commands which pilot sequence and which symbol rate to use.

[0068] Referring to the above, note that the code can be obtained from a set of Gold+1 codes. Specifically, when the symbols are bits, the codes of the set of orthogonal codes may be selected to enjoy "balanced characteristics" or "substantially balanced characteristics", and accordingly, each code has "balanced characteristics" such that for each code in the set of codes, the number of entries having a first logical value (e.g., a first binary value) is the same as the number of entries having a second logical value (e.g., a second binary value) different from the first logical value. According to an example, the first pilot sequence and the second pilot sequence may be modulated according to PAM-2 [pulse amplitude modulation] modulation [e.g., each bit of the sub-sequence may be represented by the emission of light at a predetermined wavelength during a predetermined time slot if it is 1, and represented by the absence of emission during the predetermined time slot if it is 0, and vice versa].

[0069] FIG. 3 shows a distributed system 300 including a base station 302 and at least one mobile device 350. The base station 302 may include, for example, an adjuster 310 and a plurality of adjuster-side devices 320 that may be, for example, fixed-position devices 320a and 320b (there may be a different number of fixed-position devices). The fixed-position devices 310It may be connected to the conditioner 310 via an electrical connection or a wireless connection 390. In this example, the connection 390 is shown as having a star topology, but other topologies (e.g., bus topology, side-to-side topology, etc.) may be used. In the example, the base station 302 may include the conditioner 310 and at least one stationary device 320 within a single device. The at least one stationary device may be regarded as a relay endpoint (REP). Each stationary device 320 may be optically connected to at least one mobile device 350 (e.g., the mobile device 350a in FIG. 3, or 350a and 350b in FIGS. 4a and 4b) via an optical channel 395. The mobile device 350 may be an endpoint (EP) and can form a network with the base station 302. The stationary device 320 and the mobile device 350 intend to communicate via the optical channel 395. Therefore, the stationary device 320 and the mobile device 350 do not communicate via an electrical connection or a wireless connection. However, it should be noted that in some examples, it is not necessary to have a conditioner master device 310, not necessary to have a plurality of stationary devices 320, the device 350 is not necessarily a mobile device, and the stationary device 320 is not necessarily in a fixed position.

[0070] The elements shown in FIG. 3 are for illustrative purposes only, and some of them may not be present, but it should also be noted that some other units may be present. For example, FIG. 3 does not show units that enable the transmission and reception of payloads, which are not the subject of this specification, but of course, they are implemented within devices 320 and 350. Device 320 may include an adjuster-side interface 322 for making an electrical or wireless connection 390 with an adjuster (master device) 310. Thus, interface 322 can provide commands to the positioning device 320 for transmitting a pilot sequence (and / or for determining which symbol rate to use, and / or for signaling the symbol rate and / or the selected pilot sequence to device 350) at a fixed position. Device 320 (320a, 320b) may include a pilot sequence generator 324 that can generate a pilot sequence. Specifically, pilot sequence generator 324 can construct the first pilot sequence and / or the second pilot sequence described above and can select either the first pilot sequence or the second pilot sequence. The determination of pilot sequence generator 324 may be based, for example, on an explicit command from adjuster 310 or on other criteria. The positioning device may include a storage unit 100 that stores codes that can be used to define a pilot sequence. Storage unit 100 may be exactly as in the example of FIG. 1a (see above) and thus not repeated. Thus, pilot sequence generator 324 can determine which pilot sequence is used. Device 320 (320a, 320b) may include an optical interface 326 for transmitting the selected pilot sequence to device 350 via an optical channel 395. Thus, either the first pilot sequence or the second pilot sequence may be transmitted via optical channel 395.As described below, it may be possible to transmit multiple different first or second pilot sequences within a single pilot signal.

[0071] Device 350 (e.g., a mobile device) may include an optical interface 356 for receiving the pilot sequence transmitted by the fixed-position device 326. Thus, there is an optical connection 395 between the optical interfaces 226 and 356. Device 350 may include an impulse response analyzer 358 that can analyze a pilot sequence (pilot signal) obtained from device 350. Thus, the input response analyzer 358 can analyze the impulse response and / or other characteristics of the optical channel 395. The mobile device 350 may include a storage unit 100 in which a pilot sequence and / or code is stored (as in the case of FIG. 1a, for example). Of course, when the impulse response analyzer 358 has obtained the impulse response, the mobile device can retransmit the value of the impulse response information (or other channel information) to the base station via the same optical channel 395 (the connection of this last information chain is not shown in FIG. 3).

[0072] In some examples, the two fixed-position devices 320 (320a, 320b) shown in FIG. 3 can cooperate. In the above example, for the fixed-position device 320, since power consumption is generally not important on the base station side, a battery or other energy storage unit is not shown. Nevertheless, in some examples, this can also be done. Generally speaking, in the case of the fixed-position device 320, it is presumed that it is a decision by the adjuster 310 rather than a decision based on the internal state. Nevertheless, the first or second sequence may be selected based on, for example, the charge state of the battery in the mobile device 350 (e.g., if the mobile device 350 signals that the battery charge has fallen below a predefined minimum threshold). Thus, the fixed-position device 320 (320a, 320b) or more generally the base station 302 can be a transmitter that selectively transmits either the first pilot sequence or the second pilot sequence. Alternatively or in addition, the transmitter can be the mobile device 350 (350a, 350b). In this case, the mobile device 350 may include a pilot sequence generator 354 that can generate a pilot sequence as described above (similar to the pilot sequence generator 324 described above). For example, the pilot sequence generator 354 can determine whether to use pilot sequences such as S A , S AC , S ABCD etc. The code storage unit 100 may also be used.

[0073] In an example, the transmitter can be a transmitter that transmits a pilot signal including a pilot sequence including a plurality of symbols (e.g., 8 pilot sequences within the same pilot signal or at least one or a plurality of pilot sequences of different numbers). The plurality of symbols can include at least one set of equally spaced symbols (e.g., S A or S AC ), and at least one second set of equally spaced symbols inserted between the symbols of at least one first set of equally spaced symbols (e.g., if at least one first set of equally spaced symbols is S A then S C , if at least one first set of equally spaced symbols is S AC then S BD ). The transmitter can select at least one first set of equally spaced symbols (S A , S AC ) such that each first set of equally spaced symbols represents a respective code, or at least one second set of equally spaced symbols such that each second set of equally spaced symbols represents a respective second code. For example, each set of equally spaced symbols can be S A , S B , S C, S D can be, and the transmitter can determine to transmit either two first sets S A and S C (or S B and S D ). In other cases, at least one first set of equally spaced symbols may only include subsequent S A , and at least one second set of equally spaced symbols may only include the sequence S C . When another transmitter transmits, the other transmitter (the second transmitter) can perform a similar operation in particular with a first additional code (e.g., S A , S AC ) and a second additional code (S C , S BD ) where the code selected by the second transmitter is orthogonal to the code transmitted simultaneously by the first transmitter. Basically, in detail, when the same examples as described above (e.g., the examples described with respect to FIGS. 1a, 1b, and 2) are used, S A is replaced with S E , S C is replaced with S G , S B is replaced with S F , S D is replaced with S H .

[0074] FIG. 3 also shows a battery or other type of energy storage unit 362 that can supply power to the entire mobile device 350 and that can store energy in chemical form and / or can be a capacitor such as a supercapacitor. Arrow 363 refers to charging information that can be used, for example, to determine the symbol rate used to transmit a pilot sequence. Specifically, when the charge is below a predetermined charge threshold, it may be preferable to transmit the pilot sequence at a first lower symbol rate (and transmit the first pilot sequence) rather than at a second higher symbol rate (and a second pilot sequence) (and which can be all subsequent payload data). The selected pilot sequence may be transmitted to the positioning device 320 via a channel 395 (e.g., an optical channel, or other wireless or wired channel), and the positioning device 320 can acquire the pilot sequence via its interfaces 326 (e.g., optical interfaces). The positioning device 320 may include an impulse response analyzer 328 that can process the pilot sequence received by the interface 326 (e.g., an optical interface) and acquire impulse response information. Here, it is shown that impulse response information or other channel information can be provided to the regulator 310. Specifically, when a plurality of positioning devices 320 are connected to the regulator 310, it is possible to better know the performance of the channel 395 (e.g., an optical channel). In particular, when the charge is low and the device 350 is a receiver, the pilot sequence (pilot signal) received at a reduced symbol rate (a reduced bit rate such as half the bit rate at which the pilot sequence was transmitted) can be sampled to reduce the sampling consumption (in which case the pilot sequence transmitted by the transmitter 320 is S AC If so, device 350 is S A or S C either of S ACIt only reads the subsampled version, but in either case, it is possible to obtain other information about the channel, such as the impulse response or phase information).

[0075] In the example of FIG. 3, neither device 320 nor device 350 needs to transmit a pilot sequence. If the transmitter that transmits the pilot sequence is the fixed-position device 320, the mobile device 350 may lack the pilot sequence generator 354. On the other hand, if the mobile device 350 is the transmitter that transmits the pilot sequence, the fixed-position device 320 may lack the pilot sequence generator 324. In other examples, the mobile device 350 does not necessarily determine the symbol rate based on the battery charge state. In other examples, the rate selection (and / or the selection between the first pilot sequence and the second pilot sequence) may be made based on other criteria. For example, it may be the conditioner 310 that transmits some signaling that requires a specific rate and / or a specific pilot sequence via the channel 395 (e.g., an optical channel or other wireless or wired channel).

[0076] There does not necessarily have to be only a single mobile device 350, but in principle, there can be several devices (e.g., the two mobile devices 350a and 350b in FIGS. 4a and 4b) that are not determined. As shown in FIG. 4b, if there is another device 350b (that transmits its pilot sequence) in addition to the device 350a (that transmits its pilot sequence), in principle, it may cause interference. However, thanks to the strategies described above (e.g., by using the pilot sequences S AC and S EG ), the interference between different devices transmitting pilot sequences simultaneously may be minimized.

[0077] Regardless of whether the receiver is device 320 (320a, 320b) or device 350, the receiver is configured to evaluate an input response based on a pilot sequence transmitted by the transmitter. Specifically, the pilot sequence received by the receiver may be considered to be transmitted by the transmitter at either a full data rate (e.g., full symbol rate or bit rate) or a reduced data rate (reduced symbol rate, reduced bit rate or symbol rate). For example, the full symbol rate may be a second, higher symbol rate, and the reduced symbol rate may be a first, lower data rate (symbol rate).

[0078] The pilot sequence at the full symbol rate may be considered to include a sequence at a first reduced symbol rate (e.g., A1, A2, A3, A4) and a sequence at a second reduced symbol rate (e.g., C1, C2, C3, C4). Thus, the receiver can evaluate the channel impulse response using the sequence at the first reduced symbol rate (A1, A2, A3, A4) or the sequence at the second reduced symbol rate (C1, C2, C3, C4) by sampling at the second reduced symbol rate. In some examples, the receiver may · a first reception mode by sampling at a reduced symbol rate, and · a second reception mode by sampling at the full symbol rate, where the impulse response is evaluated using the pilot sequence and can select one of the reception modes. The receiver is the code defined above (e.g., S A 、S C 、S B 、S D 、S E 、S G 、S F 、S H 、S AC 、S BDIt can utilize , and thus can receive the pilot sequence at either the first symbol rate or the second higher symbol rate.

[0079] Similar to the example made for the transmitter, the receiver can perform sampling at, for example, the first or second symbol rate (full data rate) thanks to the charging information (such as information 363). Similarly, the receiver 320 or 350 can determine to perform reception via sampling defined by the symbol rate considering, for example, a criterion including the charging state of the transmitter. In the example, the receiver does not necessarily have to accurately know which pilot sequence is being transmitted by the transmitter, but can recognize it based on the received signal (such as an optical signal). Thus, when the receiver receives a specific pilot sequence, it may be able to recognize it by checking the correspondence between the received signal and a pre-stored code.

[0080] Basically, when sampling at a reduced symbol rate (data rate) or more specifically a bit rate, the receiver can jump a predetermined fixed time distance between different symbols, for example, can acquire only the symbols of a specific sub-sequence (or code) and / or only the symbols. If the sampling has an offset of half a moment, different sequences are sampled. An example is provided in FIG. 1a. For example, if the pilot sequence S AC is being transmitted at the second high sampling rate, the receiver can sample at the first low sampling rate, for example, at the moment corresponding to A1, at the moment corresponding to A2, at the moment corresponding to A3, and at the moment corresponding to A4 for sampling. Therefore, for S where the pilot sequence is transmitted at the second high sampling rateAC That is, when the receiver samples at a lower first symbol rate, the receiver can either obtain sub-sequences A1, A2, A3, A4 or obtain C1, C2, C3, C4 (sub-sequences A1, A2, A3, A4 are lost). When the receiver samples at a second high symbol rate, the receiver obtains the complete pilot sequence A1, C1, A2, C2, A3, C3, A4, C4.

[0081] The pilot sequence is S as shown in Figure 1a ABCD That is, when the receiver samples at the complete maximum (second) symbol rate, the complete pilot sequence S ABCD = A1, B1, C1, D1, A2, B2, C2, D2, A3, B3, C3, D3, A4, B4, C4, D4 is received. When the receiver samples at half the sampling rate, the receiver receives only either the sequence S AC = A1, C1, A2, C2, A3, C3, A4, C4 (symbols B1, D1, B2, D2, B3, D3, B4, D4 are lost), or the sequence S BD = B1, D1, B2, D2, B3, D3, B4, D4 (symbols A1, C1, A2, C2, A3, C3, A4, C4 are lost). Nevertheless, even in this case, the impulse response can be evaluated and the energy required for sampling is still reduced. (This is the third example above)

[0082] The pilot sequence S ABCD is being transmitted, it is also possible for the receiver to sample at an even lower data rate (symbol rate), for example 1 / 4 (for example, the second example above). In this case, the receiver obtains, for example, a down-sampled version of the pilot sequence S A = A1, A2, A3, A4 that constitutes the pilot sequence S ABCD . However, in the case of an offset, the down-sampled version of the pilot sequence S ABCD is S B=B1, B2, B3, B4, S C =C1, C2, C3, C4, or S D =Any of D1, D2, D3, D4. Nevertheless, it is still possible to evaluate the impulse response even with a downsampled version of the acquired pilot sequence. (Note here that "downsampled version" does not necessarily mean that the values of other codes are actually sampled and then discarded. It can be obtained by simply sampling the data sample version at a reduced symbol rate).

[0083] This example may be used in a multiple-input multiple-output (MIMO) or multiple-input single-output (MISO) architecture. It is possible to perform the simultaneous transmission of (for example, as previously described with reference to FIG. 3) pilot sequences. Different transmitters may be synchronized, for example, by an adjustment master device 320 that synchronizes them via an electrical connection or a wireless connection, such that two fixed-position devices 320 may ultimately be synchronized with each other. Thus, when transmitting or receiving, the two devices 220 may ultimately be synchronized with each other. Nevertheless, there may also be synchronization between the transmitter and the receiver (for example, 320, 350). This may be obtained, for example, via a synchronization protocol in which beacon signals are transmitted at regular time intervals such that the device 350 synchronizes with the device 320. When the beacon signal transmitted by the device 320a and / or 320b (which serves as the receiver since it is intended to receive the pilot signal) is received by the device 350 (350a, 350b) (which serves as the transmitter since it is intended to transmit the pilot signal), each device 350 (350a, 350b) synchronizes to the beacon signal and transmits a pilot signal (pilot sequence) according to the synchronization obtained from the beacon signal. Thus, the first device 350a transmits a pilot sequence (for example, S ACcan send, and the second device 350b can send its pilot sequences (e.g., S EG ) that are interleaved and synchronized with each other. It is also possible for devices 320a and 320b to synchronize with each other. In this case, it is easier for the adjuster 310 to synchronize them (e.g., via a common clock electrically provided to both devices 320a and 320b) so that devices 320a and 320b transmit in cooperation synchronously (e.g., the first pilot sequence S AC transmitted by device 320a, and the second pilot sequence S EG transmitted by device 320a).

[0084] Symbols may be transmitted, for example, via modulation PAM-2, and as a result, only two binary values (e.g., +1, -1, or alternatively 1 or 0) may be allowed (thus, symbols may be regarded as bits). Specifically, it is preferable to have a balanced code to prevent baseline wander, and thus it is preferable to use alternative codes in which each code of a set of orthogonal codes enjoys a so-called "balance property" that has a ratio between the number of 1s that are 1 and the number of 0s. For example, it is possible to have codes of 128, 256, 512, 1024 symbols (e.g., bits), or more generally a number that is a power of 2 (or in some cases another even number). If there are at least 8 codes within a single defect, it is specifically possible to have up to 56 transmitters that transmit pilot sequences.

[0085] In the above example, "commonplace codes" may be excluded from the set of codes. For example, a pilot sequence that is always one binary value (e.g., 1 or 0, or +1 or -1) may generally not be permitted. Also, the sequence of the first pilot sequence is transmitted by the second pilot sequence, but the sequence of the second pilot sequence is not transmitted by the first pilot sequence. In some examples, one single sequence does not include a repetition of a selected set of equally spaced symbols (e.g., if S A is selected, it is not repeated within the same pilot sequence). Additionally or alternatively, in some examples, when one set of equally spaced symbols is transmitted, none of the transmitters transmitting simultaneously transmit the same set of equally spaced symbols (however, in that case, it is preferable that they simultaneously transmit at least one set of equally spaced symbols representing a code orthogonal to the code represented by the set of equally spaced symbols currently being transmitted by the transmitter, and if they transmit at a higher symbol rate, they are not orthogonal to the code represented by the set of equally spaced symbols currently being transmitted by the transmitter, but at least one orthogonal code can also transmit other symbols related to the codes simultaneously transmitted by the other transmitters). The code can generally be a pseudo-random code.

[0086] The codes for the first transmitters 320a or 350a stored in the storage unit 100(100a) may be stored only in a single composite code S A formed by interleaving the codes S C 、S B 、S D 、S ABCD If the first sequence transmitted is S A (A1, A2, A3, A4), the first sequence is interleaved with other codes within the composite code S ABCD (here also S A= can represent the codes shown as A1, A2, A3, A4. Also, the code S C = C1, C2, C3, C4, S B = B1, B2, B3, B4, S D = D1, D2, D3, D4 are such that each entry of each of the interleaved codes is at an equal interval position with respect to all the entries that precede or follow the same code, and with respect to each other and the code S A (A1, A2, A3, A4) is interleaved. Basically, the composite code S ABCD The different codes within are offset from each other. In particular, S AC = A1, C1, A2, C2, A3, C3, A4, C4 and S BD = B1, D1, B2, D2, B3, D3, B4, D4 can also be regarded as two different codes that are interleaved with each other in the composite code S ABCD

[0087] The composite code may be stored in the memory unit 100 (e.g., 100a). In the example, it doesn't have to be the composite code S ABCD stored in the memory unit 100, but it can be the code S A , S C , S B , S D , or the code S AC , S BD either, and in that case other codes may be obtained. In particular, the memory unit 100 of a specific transmitter (e.g., 320a, 350a) can store any one of S A , S C , S B , S D , S AC , S BC , S ABCD In the example, however, the codes S E , S G , S F , S H , S EG , S FH , S EFGH ​It is also possible to avoid (or in any case not use) memorizing one of these. These last codes are provided to different transmitters (e.g., 320b, 350b) and may be stored, for example, in the storage unit 100b. Thus, the second transmitter can transmit with a different code than the first transmitter that transmits the above code. Thus, the additional codes S E , S G , S F , S H , S EG , S FH , S EFGH are the respective codes S used by the first transmitter to generate the first and second pilot sequences A , S C , S B , S D , S AC , S BC , S ABCD , and are orthogonal to each other. For example, if S A is orthogonal to S E , S C is orthogonal to S G , S B is orthogonal to S F , S D is orthogonal to S H , then S AC is also orthogonal to S EG , and S ABCD is also orthogonal to S EFGH , thereby minimizing interference when codes orthogonal to each other are transmitted simultaneously. Thus, the pilot sequences S AC and the pilot sequence S EG are transmitted with the symbols A1, A2, A3, A4 simultaneously for the symbols E1, E2, E3, E4, so the orthogonality of the pilot sequences S AC and S CG is guaranteed. Similarly, for the orthogonality of the sequences S BD and S FH , and also for S ABCD and S EFGH .

[0088] Techniques for efficiently storing in the memory unit 100 the codes used for the first and second pilot sequences may be as follows. 1) The second pilot sequence is stored in a predetermined order (e.g., as a composite interleaved code) such that each position of the second pilot sequence (code) to be stored corresponds to a symbol to be transmitted when the second pilot sequence is selected. 2) The first pilot sequence is obtained by selecting only some positions of the second pilot sequence (composite code) at a fixed predetermined distance. By changing the shift within the stored second pilot sequence, different pilot sequences may be selected.

[0089] For example, in the first example above, 1) The second pilot sequence S AC may be stored in the memory unit 100 as S AC = A1C1A2C2A3C3A4C4 (composite interleaved code). 2) The first pilot sequence S A may be obtained by selecting every other position of the second pilot sequence S AC stored in the memory unit 100, that is, a. A1 (the first position) is held as the first symbol of the first pilot sequence S A b. B1 (the second position) is discarded, c. A2 (the third position) is held as the second symbol of the first pilot sequence S d. B2 (the fourth position) is discarded, A e. A3 (the fifth position) is held as the third symbol of the first pilot sequence S f. B3 (the sixth position) is discarded, e. A3 (the fifth position) is held as the third symbol of the first pilot sequence S A f. B3 (the sixth position) is discarded, f. B3 (the sixth position) is discarded, g.A4 (seventh position) is held as the fourth symbol of the first pilot sequence S A and h.B4 (eighth position) is discarded. Therefore, the first pilot sequence is obtained as S A = A1A2A3A4.

[0090] For example, in the second example above, 1) The second pilot sequence S ABCD may be S ABCD = A1B1C1D1A2B2C2D2A3B3C3D3A4B4C4D4 (compound interleaved code) stored in the storage unit 100. 2) The first pilot sequence S A may be obtained by selecting every fourth position of the second pilot sequence S ABCD stored in the storage unit 100, that is, a. A1 (first position) is held as the first symbol of the first pilot sequence S A and b. B1 (second position) is discarded, c. C1 (third position) is discarded, d. D1 (fourth position) is discarded, e. A2 (fifth position) is held as the second symbol of the first pilot sequence S A and f. B2 (sixth position) is discarded, g. C2 (seventh position) is discarded, h. D2 (eighth position) is discarded, i. A3 (ninth position) is held as the third symbol of the first pilot sequence S A and j. B3 (tenth position) is discarded, k. C3 (eleventh position) is discarded, l. D3 (twelfth position) is discarded, m. A4 (thirteenth position) is the first pilot sequence SA It is held as the fourth symbol of n.B4 (14th position) is discarded, o.C4 (15th position) was discarded, p.D4 (16th position) is discarded. Therefore, the first pilot sequence is S A =A1A2A3A4.

[0091] In the third example above, 1) Second pilot sequence S ABCD is S ABCD =A1B1C1D1A2B2C2D2A3B3C3D3A4B4C4D4 (composite interleaved code) in the storage unit 100. 2) First pilot sequence S AB is the second pilot sequence S stored in the storage unit 100. ABCD may be obtained by selecting every second position of a.A1 (first position) is the first pilot sequence S AB It is held as the first symbol of b.B1 (second position) is discarded, c. C1 (third position) is the first pilot sequence S AC It is held as the second symbol of d.D1 (fourth position) is discarded, e.A2 (5th position) is the first pilot sequence S AB It is held as the third symbol of f.B2 (6th position) is discarded, g.C2 (7th position) is the first pilot sequence S AB It is held as the fourth symbol of h.D2 (8th position) is discarded, i.A3 (9th position) is the first pilot sequence S AB It is held as the fifth symbol of j.B3 (10th position) was discarded, k.C3 (at the 11th position) is held as the 6th symbol of the first pilot sequence S AB and l.D3 (at the 12th position) is discarded, m.A4 (at the 13th position) is held as the 7th symbol of the first pilot sequence S AB and n.B4 (at the 14th position) is discarded, o.C4 (at the 15th position) is held as the 8th symbol of the first pilot sequence S AB and p.D4 (at the 16th position) is discarded. Therefore, the first pilot sequence is obtained as S AC = A1C1A2C2A3C3A4C4.

[0092] Specific examples are provided below. Each of the following sequences S 1024;0 ...S 1024,7 can be the second code (here represented in hexadecimal). S 1024;0 = 6209128B710F43DC211296383A7DCB443EAC93CE1D2A26C5CFF9E1E87C62171BAE5055BC28AE1E4AA186004B5C13DCED4A9BD70CC04D4E27F041D7F6441778C14DAA8D59E2F7FB212356EB540F73779165D637779DBDB167521DF6B809E1A98A8BA5C4FA16A528269A149490BD5FFCE078BCCBB2BAFBA530A0C08463690EFFFF 16

[0093] S 1024;1 = 6D0EE739128BF00FC3ECDAD569C8437231BB41636C399C1DDFFACD099B187865EE1BD767D34CAF5160825DBE0683A1142722B05354FCBB82B4E876B6AFF1C6EF7E3EB1950A9E66C7021EDB6E14AB8A74F399E5D9CF4F1E454C6028D28C4071D62DB50865B8F2116D55291DDC9190386802208584CA8A3C33A6C7A3377AA4FFFF 16

[0094] S 1024;2 = 7AE47C0E6739038BF00FAD53A55511B72C8DCF44BF9C7C067422C97AA3C91A678125966451E755F341D18882DB7E6EFC4FEBC9A2B7932A43D47D23178F892971C1501701276A9ADE1EB86A5EA5D104941A3462E60D99588FF63AB39FC652E53F70E93A35F065BF32691242A99CDC11EFC6E8FB201484CC4AAA8CB038DCC8FFFF 16

[0095] S 1024;3 = DECC7AC07E2E650D03BB0FF452B35F6EEE5CD376328FBF87841D73F236AAA1C6E0777B1A91905618AA13B9F18F5221759137B20BCC624A5CD798D182D93C88692EBE3B7B10DA257E62D5E4A89585A5DE04A4182B98C20A6DA0A40BC54E4F3C69E7107709C021F5B545196EC640999CD7EC2B3CECFB201160CBB1AD434DC7FFFF 16

[0096] S 1024;4 = 58E7CFCC7EC07A8E742DF8E4E194AA0CB53115232C0926B04298827D9C1226154CC609E87DDA936FA9F85393BF91664DCA8A6B57A16B223DA423D047281DCE7C9B16D7A1392414DAC8E18F550F77913AB5FE05BBF48B8FA2E7724FFBE085A6703C56F1D09A89C2C11D8A42596AC644A67737110B3C6CF960131FD96E53BCFFFF 16

[0097] S 1024;5 = 433450EF5FC4EEC87A86835217A4992BC5F3CACEF2D4AC36D68FDDD8FDBD1CA5469D247996A86AA5E427D1F8545BCF2E99B225C2749FD61CC5CABBDC38702F5D490373294056B1ACE46D3061E82A174009BAB5416D33FB4B6F158885A0BB08323E47A31E81D00D4122761ACA5A596271B3EE0737890333AC7E179CE0AE99FFFF 16

[0098] S 1024;6 = AE99C33C50E7DFCC6EC085717C9A6F9B66D4BA0C353172EB5401D14FA218FD82E4A53EAAA3B1115715651C27D630AC6430D96672A2020B6829EB423DC3EBBFB028AAB13CF4D6C056499B1C65CF9668159740898D4D41EAF3037C10EAF74DD88C880DB98FDB168618757EA5BE1AC2DA669DB14BE6073F0EC3345B79E86317FFFF 16

[0099] S1024;7 = 6316AE1FC3B95025DFCF913B7AF684A6906399AA45F435CD8A1053052E09A2A105061C9D396AA48CEE97EDA71BA42EC853D9CF5B61F05D7CF4132E51BA02C4EBB8CCD050B642F4D338E9B158E35CCFAD6891973A714E4A44128EFC03EF6B0F34D8758F4A41CDDC577EE072FEA5BF1AB8252565B74BA1003E093833E28652FFFF 16

[0100] S 1024;0 ...S 1024,7 The binary values of all entries (symbols) of S (for example, when performing cross-correlation in a receiver) can be either -1 or +1, but when -1 is converted to 0 and +1 is converted to 1 (or when -1 is converted to 1 and +1 is converted to 0), hexadecimal representation may be performed, and as a result, each group of four binary values may be represented by hexadecimal numbers. S 1024;0 ...S 1024,7 From S...S, according to the required symbol rate, by selecting positions every 2 n (where n is an integer), it is possible to obtain the first pilot sequence. The higher the symbol rate, the lower n is (for example, following an inverse proportion). In particular, S as the second pilot sequence (and the first pilot sequence extracted above) 1024;0 ...S 1024,7 also forms an orthogonal set of codes, and each of S 1024;0 ...S 1024,7 is orthogonal to any other code in the set of codes. In particular, each transmitter stores one of S 1024;0 ...S 1024,7 in its memory unit 100 (100a, 100b), and each receiver stores all of S 1024;0 ...S1024,7 may be stored.

[0101] S 1024;0 ...S 1024,7 Each of them may also be regarded as a composite interleaved code that may be stored in the memory unit 100 (100a, 100b) and from which a code may be obtained. Different codes within the composite code may be associated with different shifts within the composite code. S 1024;0 ...S 1024,7 Each of them may be regarded as fulfilling the role of each of S ABCD 、S EFGH in some cases. In some cases, instead of S 1024;0 ...S 1024,7 only the downsampled versions of S 1024;0 ...S 1024,7 are used (for example, if only codes with a maximum of 512 entries are required, only the half / sampled versions of S 1024;0 ...S 1024,7 can be stored, and the downsampled versions may be selected according to a plurality of possible shifts). In some cases, the shifted versions of S 1024;0 ...S 1024,7 (for example, the shifted and downsampled versions) may be used as the composite code stored in the memory unit.

[0102] In some examples, a transmitter may be provided to transmit a plurality of pilot sequences (e.g., eight pilot sequences) in a sequence of pilot sequence slots, for example, according to a predefined time order. (FIGS. 1a and 1b show one pilot sequence slot, which may be repeated, and there may be eight consecutive pilot sequence slots.) All pilot sequence slots of the same transmission may be occupied by different pilot sequences from each other, and thus may be referred to as "variants". All pilot sequence slots of the same transmission may be occupied by a pilot sequence that is either a first pilot sequence or a second pilot sequence. For example, there may be eight pilot sequence slots (slot positions) and eight variants (e.g., variant 0 obtained from S 1024;0 variant 1 obtained from S 1024,1 ... variant 7 obtained from S 1024,7 ).

[0103] In some examples, which pilot sequence is used is signaled from the regulator 310 to the transmitter. (When the transmitter is device 320, the signaling is performed via the electrical or wireless connection 390. When the transmitter is device 350, the signaling is performed via the electrical or wireless connection 390 and may be relayed via device 320 by signaling within the channel 395 (e.g., an optical channel or other wireless or wired channel) to reach device 350.) For example, an index may be signaled. The index may be a value between 0 and 63 (or another number such as a power of two), for example. An example of the signaled index is provided by Table 1 below. Table 1 TIFF0007717967000002.tif55109 In particular, Table 1 above does not indicate whether the selected pilot sequence is a first pilot sequence (e.g., composed of 1024 symbols) or a second pilot sequence (e.g., composed of 512, 256, 128, 64 symbols, etc.).

[0104] Whether to use the first pilot sequence or the second pilot sequence may be determined based on the symbol rate (bit rate) used for transmitting the pilot sequence. An example is provided by the following table. Table 2 TIFF0007717967000003.tif129160

[0105] In this Table 2, whether to use the first pilot sequence or the second pilot sequence is selected based on the symbol rate (e.g., bit rate). The last column is at full symbol rate, and S 1024;0 ...S 1024,7 indicates that all symbols (entries) of are used to generate the second pilot sequence. The other columns are at reduced symbol rates, and the first pilot sequence is obtained by selecting only every second symbol of the second pilot sequence. Generally speaking, the higher the symbol rate, the more symbols there are in the pilot sequence (the symbol rate and the number of symbols in the pilot sequence may increase proportionally). On the other hand, the lower the symbol rate, the more the second n the number of symbols in the pilot sequence becomes larger. n

[0106] ​More generally, there may be P (e.g., P = 8) pilot sequence slot positions within the same pilot signal, such that P different first pilot sequences or second pilot sequences are transmitted at the P pilot sequence slot positions (e.g., one by one). Each of the P different first pilot sequences or second pilot sequences (or more generally pilot sequences) is obtained from a stored set having V (here, V = 8 different stored second pilot sequences, e.g., composite codes) stored (e.g., stored in memory unit 100). Thus, P*V possible combinations are implied between the P pilot sequence slot positions and the V different stored second pilot sequences, and the P*V combinations are enumerated in a predetermined order. Information regarding the P selected combinations may be obtained from the signaling, and the P selected first pilot sequences or second pilot sequences (or more generally pilot sequences) transmitted at the P pilot sequence slot positions are associated from among the P*V possible combinations. However, this information does not explain whether the first pilot sequence or the second pilot sequence is selected. In some cases, P = V = 8.

[0107] Thus, there may be two different types of information used to determine which pilot sequence to use. 1) An index that can be from 0..63 and signals which variant of the pilot signal is used at which position, but which by itself does not provide information as to whether the first pilot sequence or the second pilot sequence is used (e.g., signaled from the regulator to the transmitter) 2) Signaling information indicating whether to select the first pilot sequence or the second pilot sequence, which can be, for example, information regarding the symbol rate used

[0108] In some examples, the signaling can indicate which shift can be obtained to identify the particular code being used. Thus, the signaling can identify which composite code among a plurality of stored composite codes is selected, and which shift the interleaved code selected within the selected composite code has, in order to identify a set of equally spaced entries within the selected composite code from which the symbols of the selected sequence are obtained. In other examples, since the first code of the composite code has the privilege (highest ranking), the shift is not signaled.

[0109] An example of the above concept is shown in FIG. 5. The example shows an operation for defining which sequence is transmitted at which position or slot within the transmitter. 500 In this example, there may be a plurality (e.g., eight) of variants selected from a more major or larger group of possible sequences. The operation begins at step 502 and can proceed to step 504. At step 504, the first position slot (e.g., slot number 0) is selected. At step 506, the requested code is identified here. The identified requested code may be obtained from the signaling. At step 508, the requested code may be retrieved. For example, if the codes are interleaved with each other within the memory unit 100, a particular requested code may be obtained. For example, (e.g., S ABCD and S EFGH or possible S 1024,0 ~S 1024,7A specific sequence within may be identified. In step 510, it is possible to understand whether the first pilot sequence has been selected or the second pilot sequence has been selected. This information can come, for example, from the symbol rate being used. In case 512, since the first symbol rate is selected, symbols for the first pilot sequence will be selected in step 514. Alternatively, in 516, a second, higher symbol rate may be selected. Here, there can be two further options. Option 518 occurs when the selected sequence matches the interleaved composite code that has been memorized, in which case all symbols will be transmitted. In option 520, some symbols are selected in step 522 and some other symbols are discarded. For example, as shown in Table 2, when the symbol rate is the highest (200 MHz in Table 2) and the memorized composite code is (A 1024,0 ~A 1024,7Option 518 may be selected when all bits of [[ID=]] are used to generate the pilot sequence. Option 520 can be when the second higher rate is 100 MHz such that only the bits of the complete composite code are selected every second. Of course, in option 512, when the first pilot sequence is selected, the symbol rate is lower than that of option 518 (for example, referring to any of the first four columns of Table 2 on the condition that the second higher rate is in a column to the right of the column of the first pilot sequence). In all options 512, 518, and 520, the pilot sequence (whether first or second) is encoded at the current slot position. In step 526, it is checked whether another slot position is selected (for example, whether the pilot sequence has already been found for each of the P = 8 pilot sequences transmitted within the same pilot signal). If there are other options selected at 528, the logged position is updated at step 530 and a new iteration of method 500 is started, for example, from step 516. If it is determined at step 526 that there are no other position slots to be encoded, transition 532 transitions towards the final step 534.

[0110] Referring to the receiver, it should be noted that the receiver may be obtained as a receiver mainly configured to receive the pilot sequence and obtain channel information (such as phase information, impulse response, etc.). A process of correlating a pre-stored version of a set of equally spaced symbols may be performed to obtain channel information (such as phase information, impulse response, etc.) using some techniques known as such, and several others are also described here.

[0111] In some examples, a receiver can obtain phase information of a pilot signal from a pilot sequence within the pilot signal, and the pilot sequence includes a plurality of sets of equally spaced symbols interleaved with each other. The receiver can perform an evaluation operation to evaluate the correlation between the pilot sequence and a pre-stored version of the plurality of sets of equally spaced symbols, thereby determining a set of codes having the highest correlation with the pilot sequence in order to obtain phase information from the determination of the set of codes having the highest correlation with the pilot sequence.

[0112] The example of FIG. 6 shows a method 600 including a first operation 610 at a transmitter and at least one second operation 620 at a receiver. (Any of the above transmitters may be used, and it may be either a mobile device or a fixed-location device) The transmitter transmits a specific pilot signal having a specific pilot sequence (e.g., S AC ). At this point, it is irrelevant whether other pilot sequences are transmitted simultaneously by other / different devices (it may occur in some examples and may not occur in others). (Any of the above receivers may be used, and it may be either a mobile device or a fixed-location device) In the receiver, the following method 620 may be executed. In step 622, a pilot signal having a pilot sequence (e.g., S AC ) may be received. The pilot sequence may be digitized, for example, via an analog-to-digital converter (ADC). In step 624, the pilot signal (in its digital version) may be cross-correlated with a plurality of pre-defined sequences (representing pre-stored codes). The pre-defined sequences may be, for example, S A and S C . By cross-correlating the received pilot signal with S A and S C , respectively, correlation values CC A and CC Cmay be obtained. In step 626, the cross-correlation value is maximized (e.g., among S A and S C ) and a predefined sequence is found. For example, the cross-correlation value CC A is greater than CC C (CC C <CC A ), so it is recognized that sequence S A is received better than S C . On the other hand, if CC C is greater than CC A (CC C >CC A ), the sequence received well is determined to be S C . Thus, in step 628, it is possible to obtain phase information regarding the channel based on the predefined sequence that maximizes the cross-correlation. For example, if CC A is greater than CC C (which means that S A is received better than S C ) (CC A >CC C ), the phase of the pilot signal can be considered closer to 0° than 180°. On the other hand, if the correlation value CC C is greater than the correlation value CC A (CC C >CC A ), the phase can be considered closer to 180° than 0°. When there are three or more sequences within the same pilot signal, this process can actually be generalized in the sense that it is possible to have information regarding the phase with a higher granularity (better resolution) than the 0° / 180° granularity of the example using S AC . For example, if the pilot sequence includes sequences S A , S B , S C , and S D , the phase is 0° when (CC A is the highest cross-correlation value), 90° when (CC B has the highest cross-correlation value), (CCC when it has the highest cross - correlation value) 180°, and (when the highest cross - correlation is CC D it is possible to understand whether they are similar by 270°. Thus, different sequences correspond to different phases, for example, according to the offsets each sequence has.

[0113] In some examples, the receiver can evaluate channel information from received signals received from a plurality of pilot signals transmitted simultaneously by a plurality of transmitters, and the plurality of transmitters includes at least a first transmitter and a second transmitter. Thus, the first pilot signal transmitted by the first transmitter is at least a first pilot sequence (e.g., S A ) at a first symbol rate, where the first pilot sequence (e.g., S A ) includes at least one first set (e.g., S A ) of equally - spaced symbols (e.g., A1, A2, A3, A4), A and a second pilot sequence (e.g., S AC ) at a second symbol rate higher than the first symbol rate, where the second pilot sequence (e.g., S AC ) includes at least one first set (e.g., S A ) of equally - spaced symbols (e.g., A1, A2, A3, A4) and at least one second set (e.g., S C ) of equally - spaced symbols (e.g., C1, C2, C3, C4) interleaved therewith, AC and includes a pilot sequence selected between The second pilot signal transmitted by the second transmitter is at least a first additional pilot sequence (e.g., S E ) transmitted at the first symbol rate, where the first additional pilot sequence (e.g., S E) includes at least one first additional set (e.g., S E ) of symbols (e.g., E1, E2, E3, E4) at equal intervals, a first additional pilot sequence (e.g., S E ), and a second additional pilot sequence (S EG ) transmitted at a second symbol rate higher than the first symbol rate, where the second additional pilot sequence (S EG ) includes at least one first additional set (e.g., S E ) of symbols (e.g., E1, E2, E3, E4) at equal intervals and at least one second additional set (e.g., S G ) of symbols (e.g., G1, G2, G3, G4) at equal intervals interleaved therewith, a second additional pilot sequence (S EG ), and includes an additional pilot sequence selected between at least one first set (e.g., S A ) of symbols (e.g., A1, A2, A3, A4) at equal intervals represents at least one first code orthogonal to at least one first additional code represented by at least one first additional set (e.g., S E ) of symbols (e.g., E1, E2, E3, E4) at equal intervals, at least one second set (e.g., S C ) of symbols (e.g., C1, C2, C3, C4) at equal intervals represents at least one second code orthogonal to at least one second additional code represented by at least one second additional set (e.g., S G ) of symbols (e.g., G1, G2, G3, G4) at equal intervals, The receiver samples the received signal at a symbol rate that is either the first symbol rate or the second symbol rate, and to obtain information about the channel between the first transmitter and the receiver and information about the channel between the second transmitter and the receiver, both a set of symbols at equal intervals and a pre-stored version of the additional set (e.g., S A , S C SE S G S AC S EG ) is configured to correlate with the received signal.

[0114] When sampling at the second symbol rate, the receiver (e.g., at element 328 or 358) is at least to obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, at least one first set of equally spaced symbols (S A ) of the pre-stored version, at least one second set of equally spaced symbols (S C ) of the pre-stored version, and at least one second set of equally spaced symbols (S C ) of the pre-stored version interleaved with at least one first set of equally spaced symbols (S A ) of the pre-stored version (S AC ) at least one of the correlation between, and / or to obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, at least one first additional set of equally spaced symbols (S E ) of the pre-stored version, at least one second additional set of equally spaced symbols (S G ) of the pre-stored version, and at least one second additional set of equally spaced symbols (S C ) of the pre-stored version interleaved with at least one first additional set of equally spaced symbols (S E ) of the pre-stored version (S EG ) at least one of the correlation between can be evaluated.

[0115] Additionally or alternatively, when sampling at a second symbol rate, the receiver (e.g., at element 328 or 358) is at least to obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, at least one first set (S A ) of pre-stored versions of equally-spaced symbols, and at least one second set (S C ) of pre-stored versions of equally-spaced symbols of at least one of and the correlation between, and / or to obtain channel information regarding the channel between the first transmitter and the receiver, the received signal, at least one first additional set (S E ) of pre-stored versions of equally-spaced symbols, and at least one second additional set (S G ) of pre-stored versions of equally-spaced symbols of at least one of and the correlation between can be evaluated. Thus, it is possible to obtain information regarding the channel (e.g., impulse response).

[0116] FIG. 7 shows an example that may or may not be used in combination with the example of FIG. 6, for example. In this case, two different transmitters (e.g., one of transmitters 320a and 320b in FIG. 4a and / or transmitters 350a and 350b in FIG. 4b) can transmit simultaneously in a coordinated and synchronized manner, each transmitting its pilot sequence. For example, the first transmitter can transmit S A , S AC , or S ABCD , and the second transmitter can transmit, for example, S E , SEG , S EFGH is transmitted (for example, pilot sequences transmitted by two transmitters are transmitted simultaneously within the same pilot sequence slot of the same length, and if they are transmitted at different symbol rates, the transmitter transmitting at the higher symbol rate transmits multiple symbols simultaneously with the transmission of a single pilot symbol by the transmitter transmitting at the lower symbol rate). As shown in block 721, in channel 395, the first / second pilot sequences transmitted by the first transmitter and the first / second additional pilot sequences transmitted by the second transmitter are combined (superimposed) with each other, and thus, the receiver receives a single received signal such that the transmitted pilot sequences (S A / S AC / S ABCD of which one) and the additional sequences (S E / S EG / S EFGH of which one) are distinguished from each other. Thus, the receiver receives the received signal at 722. Thereafter, the receiver evaluates the correlation (e.g., by calculating the cross-correlation) between the received signal and a predefined set of equally spaced symbols such as S A , S AC , S ABCD , S E , S EG , S EFGH , etc. It is not always necessary for the receiver to try all the codes S A , S AC , S ABCD , S E , S EG , S EFGH . In some cases, in fact, the receiver can have knowledge of the symbol rate transmitted by each transmitter, and thus, can sample at the sample rate of the pilot sequence transmitted at the highest symbol rate, or can define the sampling rate for the low symbol rate codes transmitted by the transmitter transmitting the first low symbol rate sequence. For example, if the first transmitter transmits the first pilot sequence S Atransmits, and when the receiver knows that the second transmitter transmits the first additional pilot sequence S E , the receiver can simply sample at the first low sample rate, and (without evaluating the cross-correlation with S AC , S ABCD , S EFG , and S EFGH ) can also evaluate the cross-correlation between the received signal S A and S E .

[0117] For example, when the receiver knows that the first and second transmitters transmit the second pilot sequence S AC and the second additional pilot sequence S EG respectively, the receiver can determine whether to cross-correlate the received signal with any of the following predefined sets of equally spaced symbols (it is also possible to select only one or only two of the following three possibilities). 1. S AC and S EG 2. S A , S C , S E , S G 3. S A , S C , S AC , S E , S G , S EG S A is orthogonal to S E , S C is orthogonal to S G , and as a result, due to the fact that S AC is orthogonal to S EG , it is possible to evaluate the cross-correlation of both the pilot sequence transmitted by the first transmitter and the pilot sequence transmitted simultaneously by the second transmitter.

[0118] The first transmitter and the second transmitter transmit at different symbol rates (e.g., the first transmitter transmits the first pilot sequence S A at a first lower symbol rate, and at the same time the second transmitter transmits the second additional pilot sequence S EG at a second higher symbol rate), the receiver can (it is also possible to select only one of the following three possibilities, or only two of them), 1. Evaluate the cross-correlation of the received signal with S A , S E , and S G (e.g., when sampling at the first symbol rate or the second symbol rate), or 2. Evaluate the cross-correlation between the received signal and S A and S EG (e.g., when sampling at the first or second symbol rate), or 3. Evaluate the cross-correlation between the received signal after sampling with a simultaneous set of equally spaced symbols S A and S E and S A and S E (e.g., when sampling at the first low symbol rate) (the equally spaced symbols of S G , i.e., G1, G2, G3, G4, are destructively superimposed on the symbols A1, A2, A3, A4 of S A ), so avoid sampling during the time slots when the symbols of the set of equally spaced codes S C and S G are transmitted simultaneously can be done.

[0119] If the first transmitter and the second transmitter transmit at the same low symbol rate (e.g., the first transmitter transmits the first pilot sequence S A , and at the same time the second transmitter transmits the first additional pilot sequence S E ), the receiver 1. Evaluate the cross-correlation of the received signal with S A and S E ), or 2. Simultaneous set S of equally spaced symbols A and S E By synchronizing the sampling, the received signal and S A or S E Evaluate the cross - correlation between any of them This can be done.

[0120] Therefore, the receiver can determine whether to sample at a second higher symbol rate or at a lower first symbol rate, and to obtain information about the transmitter channel, cross - correlate (or otherwise evaluate the correlation) between the received signal (obtained from the coupling (superposition) between pilot sequences transmitted by multiple transmitters) and multiple sets of equally spaced codes. In step 726, a pre - defined set of equally spaced symbols that maximizes the cross - correlation is found. The same operations as those described above for step 626 in the example of FIG. 6 may be performed, and they are not repeated here. In step 728, channel information may be obtained. In this case, the channel information can be both information about the channel between the first transmitter and the receiver and information about the channel between the second transmitter and the receiver. This may occur, for example, when the first transmitter transmits the second sequence S AC or S ABCD and the second transmitter transmits a second additional sequence S EG or S EFGH This can follow the example described above for step 628 in FIG. 6. For example, the channel information between the first transmitter and the receiver may include phase information obtained by evaluating the cross - correlation of S A and the cross - correlation with S AC If the cross - correlation with S A is greater than the cross - correlation with S C the phase is considered to be more similar to 0° than to 180° (if the cross - correlation with S C is greater than the cross - correlation with S AIf it is found to be greater than the cross-correlation with, it is the reverse). At the same time, for example, a set S of symbols at equal intervals E and a set S of symbols at equal intervals EG By evaluating the cross-correlation between and finding the one that maximizes the cross-correlation with the received signal, similar channel information (e.g., phase information) between the second transmitter and the receiver can be obtained. The processing at the receiver is shown here by 720.

[0121] In the examples of FIGS. 6 and 7 (more generally, in examples of a receiver that receives a pilot sequence transmitted by any of the transmitters described above), typically, there is a point at which the received signal (e.g., a pilot signal received by one transmitter, or a receiver signal obtained as a combination (superposition) between a plurality of pilot sequences transmitted simultaneously and cooperating with each other) is digitized, for example, using an analog-to-digital converter (ADC). Referring to the example of FIG. 3, when the receiving unit 326 receives a pilot sequence from the transmitter 350, it may be assumed that the signal is provided to the response analyzer 328 either in analog version or digital version. Thus, either the component 326 or the component 328 may have an analog-to-digital converter. The same may apply when the transmitter is the device 320 (320a and / or 320b), and when the receiver is the device 350, the receiving unit 356 provides an analog signal to the input response analyzer 358 (and the input response analyzer 358 digitizes the signal), or the receiving unit 356 digitizes the received signal and provides the digital version thereof to the input response analyzer 358. Referring to FIG. 6, digitization may be performed between steps 622 and 624, and referring to FIG. 7, digitization may be performed between steps 722 and 724. Elements 328 and 358 are referred to as "input response analyzers", but it should be noted that they can generally be analyzers (or other means for evaluating the correlation) that analyze the cross-correlation between the received signal (e.g., a pilot sequence obtained by any transmitter) and a predefined set of codes transmitted.

[0122] In some examples, the receiver does not know which pilot sequence is being transmitted and does not know which code (equispaced symbols) is being used. This means that the receiver can cross-correlate the received signal at multiple different symbol rates. Thus, the receiver can determine how many transmitters are present and at which symbol rate they are currently transmitting. When multiple transmitters are transmitting their pilot sequences (at any symbol rate they transmit at), they can operate synchronously and cooperatively, such that they transmit symbols of codes orthogonal to each other during simultaneous time slots (e.g., in steps 710 and 715 of FIG. 7). This also holds true when there are three or more transmitters. For example, a receiver (e.g., 320, 320a, 320b) or a beacon device (which may be different from any other device and may also be one of the transmitters) transmits a beacon signal to synchronize different transmitters and different receivers (when there are two or more signals). After receiving the beacon signal, all transmitters and receivers re-synchronize and determine the time slots in which each symbol of the pilot sequence is transmitted (and also for each pilot sequence slot).

[0123] Some of the above examples are provided by presuming that sequences having the same number of symbols (corresponding to codes of the same length) are transmitted simultaneously (e.g., within the same pilot sequence slot). Thus, while the first transmitter transmits code S A , it may be presumed that the second transmitter transmits a first additional code S A orthogonal to S E . Basically, it can be that different orthogonal sequences can be transmitted by the first and second transmitters at the same symbol rate (thereby selecting a set of codes and sequences of the same length). Nevertheless, as disclosed in other examples above, this is not strictly necessary. For example, while the first transmitter transmits a first pilot sequence S A at a first lower symbol rate, the second transmitter transmits a second pilot sequence S E formed by two sets of equally spaced sequences S G and S EG interleaved with each other.can be transmitted. This is generally not a problem. In fact, during each time slot in which each symbol A1, A2, A3, A4 of the first pilot sequence transmitted by the first transmitter is transmitted, two consecutive adjacent symbols E1, G1, E2, G2, E3, G3, E4, G4 are transmitted simultaneously, respectively. More specifically, while symbol A1 is transmitted at the first lower symbol rate, within the same time slot in which A1 is transmitted, both symbol B1 and D1 are transmitted within two time slots at the second highest symbol rate (the second highest symbol rate is a multiple of the first lower symbol rate). For example, when the first transmitter transmits S A and the second transmitter transmits S EFGH . In this case, the second transmitter transmits S A at a symbol rate four times higher than the symbol rate at which S EFGH was transmitted. Thus, while symbol A1 is transmitted within one time slot at the first lower symbol rate, four consecutive symbols E1, F1, G1, H1 (each being one of four sets of equally spaced symbols S E , S G , S F , S H transmitted by the second transmitter in the second pilot sequence SFGH) are transmitted.

[0124] Even when the sequence transmitted at the second higher symbol rate includes at least one set of equally spaced symbols that is not orthogonal to any set of equally spaced symbols transmitted within the first sequence by the first transmitter, this is generally not a problem at the receiver, provided that at least one additional code transmitted by the second transmitter at the second higher symbol rate is a symbol of a set of equally spaced symbols that is orthogonal to what was transmitted simultaneously within the first sequence by the first transmitter. For example, S A is orthogonal to S E , and S C is orthogonal to S G . However, in some examples, S A while SG is orthogonal to S C and S E is not required to be orthogonal to. Nevertheless, simultaneously with each other, S A is transmitted by the first transmitter within the first pilot sequence at a first lower symbol rate, and the second sequence S EG is transmitted by the second transmitter at a second higher symbol rate, A1 is transmitted simultaneously with symbols E1 and G1, A2 is transmitted simultaneously with symbols E2 and G2, and so on. However, the set of equally spaced symbols A1, A2, A3, A4 is orthogonal to the set of equally spaced symbols E1, E2, E3, E4, but not orthogonal to the set of equally spaced symbols G1, G2, G3, G4. Therefore, at the receiver, interference is minimized within the "second symbol rate" time slots in which E1, E2, E3, E4 are transmitted (due to orthogonality), and resolution occurs between symbols A1, A2, A3, A4 and symbols G1, G2, G3, G4. This does not pose a problem at the receiver in the following two cases.

[0125] 1. When the receiver samples at a second higher symbol rate, the receiver recognizes the (orthogonal sets of equally spaced symbols S A and S E ) transmitted simultaneously between some time slots, so it does not find any valuable sequence within the time slots where symbols A1, A2, A3, A4 are superimposed on symbols E1, E2, E3, E4. 2. The receiver samples at a first lower symbol rate, but synchronizes with the time slots in which the symbols E1, E2, E3, E4 of the second pilot sequence S EG are transmitted. Therefore, the receiver can recognize the sequences S A and S E as being transmitted by the first transmitter and the second transmitter respectively, and does not recognize any valuable transmission between the interleaved time slots. The first transmitter is S Atransmits a first pilot sequence of the form, and the same thing happens when a second transmitter transmits a second pilot sequence of the form S EFGH This also occurs when transmitting a second pilot sequence of the form. In general, it is not necessary for only two transmitters to transmit simultaneously. Multiple transmitters can transmit during the same time slot.

[0126] In the above example, the transmission of pilot sequences by wireless transmitters, specifically optical transmitters, is mainly referred to. In the case of an optical transmitter, the communication unit (e.g., 326, 356 in FIG. 3) may be formed by an optical transmitter (e.g., a light-emitting diode, LED), and the optical receiver can include, for example, a phototransistor. The LED and the optical Receiving machine may be arranged in the same unit (which may be, for example, communication units 326 and / or 356). In the case of wireless transmission, the communication units 326 and 356 can be antennas that transmit and / or receive at a radio frequency. In the case of ultrasonic waves, the communication units 326 and 356 can be, for example, speakers configured to generate ultrasonic (acoustic) waves for transmitting signals, and the receiver can be a microphone or other acoustic receiver for the receiving unit. Also, in this case, they can coexist within the same communication unit (e.g., 326, 356). It is also possible to have wired communication where the channel is a wired channel rather than a wireless channel. There may be at least one wire (e.g., two wires) and / or at least one cable (e.g., a number of cables). In this case, the channel 395 is a non-wireless channel.

[0127] In the above example, the adjuster 310 can assign a particular set of codes (e.g., a pre - defined sequence) to any transmitter and / or any receiver. The assignment, in some examples, may be actuated by signaling some particular codes (the codes are already known to each transmitter and / or each receiver) being used, and can be during the initialization procedure. In some cases, the adjuster 310 can explicitly signal the codes used by each transmitter and / or each receiver. These operations may preferably be performed during the initialization procedure. In this case, the storage unit 100(100a, 100b) in each receiver and / or each transmitter may also be accessed to write the codes signaled by the adjuster 310.

[0128] In other examples, the adjuster 310 may be connected to the device 320(320a, 320b) (e.g., a positioning device) via the electrical connection 390. In this case, specifically, when the positioning device 320(320a, 320b) simply relays the pilot sequence transmitted by the transmitter 350 or re - transmits the pilot sequence obtained from the adjuster 310 via the electrical connection 390 and re - transmits it to the receiver 350, the storage unit 100(100a, 100b) in FIG. 3 may not be locally present within the positioning device 320(320a, 320b). In this case, the storage unit can thus be local to the adjuster, and the transmitter or receiver simply operates as a relay. When the adjuster 310 provides a code to the transmitter, the provision of the code can also be performed via a relay. For example, this is the case in FIG. 3, where the adjuster 310 can provide a code to the mobile device 350 via the electrical wireless connection 390, the positioning device 320(320a, 320b), and the channel 395 at the receiver 356, and as a result, the device 350 stores the code in the storage unit 100(110a).

[0129] In the above example, the regulator 310 can assign a specific set of codes (e.g., a pre - defined sequence) to any transmitter and / or any receiver. The assignment, in some examples, may be obtained by signaling some specific codes (the codes are already known to each transmitter and / or each receiver) that are used, and this can occur during the initialization procedure. In some cases, the regulator device 310 can explicitly signal the codes used by each transmitter and / or each receiver. These operations may preferably be performed during the initialization procedure. In this case, the storage unit 100 (100a, 100b) in each receiver and / or each transmitter may also be accessed to write the codes signaled by the regulator 310.

[0130] In other examples, the regulator 310 may be connected to the device 320 (320a, 320b) (e.g., a positioning device) via the electrical connection 390. In this case, specifically, when the positioning device simply relays the pilot sequence transmitted by the transmitter 350 or re - transmits the pilot sequence obtained from the regulator 310 via the electrical connection 390 and re - transmits it to the receiver 350, the storage unit of Figure 3, 100 (100a, 100b), may not be locally present within the positioning device 320 (320a, 320b). In this case, the storage unit can thus be local to the regulator, and the transmitter or receiver simply operates as a relay. When the regulator 310 provides a code to the transmitter, the code can also be provided via the relay. For example, in the case of Figure 3, the regulator 310 can provide a code to the mobile device 350 via the electrical wireless connection 390, the positioning device 320 (320a, 320b), and the channel 395 at the receiver 356. As a result, the device 350 stores the code in the storage unit 100 (110a).

[0131] In an example, the connection 390 of FIG. 3 can also be generalized. This means that the conditioner 310 may be connected via an electrical connection, via a radio frequency connection, via an optical connection, to a wired connection (e.g., a cable connection). Note that in some examples, the connection 390 may not be distinguished from the communication in channel 395. For example, the conditioner can be a device different from the devices 320a, 320b, 350, 350a, 350b of FIGS. 3, 4a, and 4b. Thus, the conditioner does not necessarily have to be connected to different fixed-position devices it is connected to via a star connection, but the conditioner 310 can also be one of the devices within a group of devices (which can be a group of mobile devices).

[0132] As described above, the conditioner 310 does not necessarily have to be electrically connected to (or be) a transmitter or a receiver. The conditioner 310 can signal a requirement to transmit at a particular rate (e.g., a first symbol rate and / or a second symbol rate or any other symbol rate), and / or any transmission of any particular pilot sequence (e.g., a first pilot sequence, a second pilot sequence, or any other pilot sequence). The same applies to the receiver. In some cases, the conditioner 310 can require the receiver to operate at a particular symbol rate (e.g., a first signal rate, a second symbol rate, or any other symbol rate), and / or to read the sequence transmitted by the transmitter by comparing the received signal 7 with any pre-defined sequence of symbols (any pre-defined code).

[0133] Consideration Regarding the solution, the present invention proposes a new type of sequence that generates additional orthogonal sequences for higher clock rates by combining orthogonal sequences according to a specified method. In this case, the orthogonality between sequences of different clock grades is maintained. Therefore, the proposed method is also extensible to future systems operating at even higher clock rates.

[0134] The generation of sequences is described based on the following example. 1) A set of selectable basic sequences may be selected (S A ~S H ). In this case, s A and s E , s C and s G , s B and s F , as well as s D and s H must be sequences that are orthogonal to each other. 2) The selected sequences are then combined into longer sequences according to the method shown in the drawings. 3) This method may be repeated multiple times, with the length of the sequence doubling in each instance while the number is halved.

[0135] Due to the orthogonality of each described in 1) and the definition of orthogonality TIFF0007717967000004.tif968 s AC and s EG , as well as s BD and s FH are orthogonal to each other, and the same applies to s ABCD and s EFGH . For example, if s AC and s EG are transmitted (synchronously) by two antennas of a transmitter and received at the receiver at half the rate, under the assumption of ideal undersampling, depending on the phase position, s A is sE is received in duplicate with, or s C is s E is received in duplicate with. Thus, orthogonality is maintained in this case as well. Here, the concept has been used and tested in detail for sequence lengths of N = 64 to N = 1024 and is thus adaptable. Additionally, in these simulations, it also operated with non-ideal and realistic undersampling by pre-low-pass filtering. Extended Gold sequences [3] that satisfy the required orthogonality properties were used as the basic sequences. The basic sequences used are shown in the appendix of the master's thesis.

[0136] The possibility of operating the receiver at a lower clock rate (first reduced symbol rate) makes it possible to significantly reduce the energy consumption of the receiver without losing the ability to estimate the orthogonal channels of several users. This function is particularly useful for battery-operated devices. The sequences are defined by the standard and must be used to conform. Potentially, it is possible to use other orthogonal basic sequences according to the same method, which is the reason why not only the specific sequences but also the general method of their construction should be patented. However, in the literature known to the author, there are no binary sequences other than the Gold sequences suitable for the intended purpose. This technique may be used, for example, in the fields of wireless or wired communication systems with several users, such as LiFi, passive optical networks, channel estimation of CATX Ethernet, and binary communication systems. The pilot sequence makes it possible to measure the phase and amplitude responses of the MIMO channel between a plurality of transmitting transmitters and a plurality of receiving transmitters. The MIMO pilot is composed of pre-defined sequences. In the case of MIMO pilots, it may be stated that iteration, FEC, and line coding should not be applied.

[0137] In the example, assume that the transmitter includes 0 to 8 pilots in each pilot slot of the transmitted pilot sequence as shown below. The number of pilot slots in the pilot sequence must be equal to the number indicated by the MIMO pilot slot field in the PM PHY header.

[0138] TIFF0007717967000005.tif36169

[0139] Each transmitter can transmit exactly one pilot variant within a specific slot. The selection of the slot and variant of the transmitted pilot depends on the transmitter index, Slot position = floor(<transmitter index> / 8) Variant = <transmitter index> modulo 8 and is calculated by (floor(<transmitter index> / 8) is the integer result of the integer division between the transmitter index and 8 or another number, and <transmitter index> modulo 8 is the remainder of that integer division). This can be a signaling index that provides a specific first or second combination for each of the V position slots, but this is not information indicating whether to select the first pilot sequence or the second pilot sequence. Table 1 above lists the relationship between the variant, slot position, and transmitter index. The assignment of the transmitter index to the transmitter is implementation-specific.

[0140] In addition, assume that the actual pilot sequence used to transmit the pilot sequence varies according to the OCR (symbol rate) indicated by the MCS in the MCS ID field within the PHY header. Note - This construction method enables the use of a lower OCR (Variable Sampling Factor, VSF) at the receiver, but it is still possible to estimate the MIMO channel at the maximum resolution determined by the OCR of the transmitter. This is because all simultaneously transmitted MIMO pilots are guaranteed to be orthogonal at any OCR. Table 2 above lists the sequences used for each combination of OCR and variant. For the i-th variant, respectively, the basic sequence S 1024;i serves as the basis for constructing the transmitted pilots. Based on the OCR, starting from the first bit of the basic sequence, only every n-th bit of the basic sequence is assumed to be transmitted, with n = 2 4-OCR being the case. All other bits are assumed to be excluded from transmission. Thus, Table 2 above can provide that the information indicating whether to select the first pilot sequence or the second pilot sequence is different from the signaled index.

[0141] In slots where a particular transmitter does not transmit a pilot, the transmitter is assumed to remain silent. For example, the following table depicts a single pilot sequence transmitted via 16 transmitters using two pilot slots, each having 8 variants, for including MIMO pilots. The receiver can thus estimate the channel between the 16 transmitting transmitters and the single receiving transmitter.

[0142] TIFF0007717967000006.tif62167

[0143] Some features that can be used in this technique: - They use Gold sequences extended to the shortest stage - They can combine sequences using the presented method to create longer corresponding ones - A lower sample rate can be used in the receiver. - Orthogonality is maintained between "stages" (a·b = Σa i ·b i = 0) - Assumed orthogonality: s E orthogonal to s A s, G orthogonal to s C s, F orthogonal to s B s, H orthogonal to s D , thereby, s EG orthogonal to s AC as well as s FH orthogonal to s BD and s EFGH orthogonal to s ABCD occurs. Ideal subsampling in synchronous transmission maintains orthogonality. The principle can be adapted to the lengths and set sizes required by the PM-PHY.

[0144] As described above, in the receiver, analog data from the optical front end of the receiver (e.g., 326, 356) is converted to the digital domain using an analog-to-digital converter (ADC). An ideal model of the ADC samples the input signal within an infinitely small time span and thus does not perform averaging, does not limit the bandwidth, or apply other distortion effects. (S ABCD transmitted as) An exemplary received pilot sequence may simulate the ideal ADC behavior under ideal conditions (no distortion, no noise) and be resampled by the receiver at half the transmission rate (or another integer such as a power of 2 increased by an integer exponent). As described above, this generates two possible sequences at a lower symbol rate depending on the starting sample, and in principle, it is S AC or S BD obtained in either case (S AC or S BDAny one of them may be obtained). This leads to the following available mechanisms: Specifically, when the pilot sequence is transmitted over a non-distorted channel applying only delay under complete conditions, a receiver operating at half the symbol rate receives a shifted version of one of the subsampled sequences. Depending on which of the two is received and the amount of shift that can be found, for example, by cross-correlation, it can determine (find out) the phase position of the transmitted sequence with an accuracy of "1 / transmitter symbol rate" seconds. When constructing the proposed pilot sequence, a bottom-up approach may be taken, meaning that the shortest sequences are generated first and then combined to form larger sequences using the ABAB method, an example of which is shown in Figure 2. As explained above, each of A1, A2,... represents a set S of equally spaced symbols (representing codes) A bits (symbols) belonging to, and B1, B2,... represent bits (symbols) belonging to a set S of equally spaced symbols (representing codes) B and so on. To achieve orthogonality for all sequence lengths in this example, the sequences S A S B S E and S F are orthogonal sets of codes, and S C S D S G and S H are selected to form (at least S E orthogonal to S A S G orthogonal to S C or all of them may be orthogonal to each other). This ensures that the sequences S AC and S EG、 as well as S BD and S FH also form orthogonal sets. In the final stage, S ABCD and S EFGHThey are also orthogonal. This is because in this case, the same elements of the sequence are added when constructing the dot product. As a result, in this example, there are K = 2 sets of M = 4 orthogonal sequences required, where K is the number of the longest sequences and M = 2 L-1 and L indicates the number of available symbol rates. To adapt the method to higher sequence lengths for the PM-PHY, K may be set to the minimum set size, e.g., K = 8. There may be five possible clock / symbol rates (12.5, 25, 50, 100, and 200 MHz) for the PM-PHY, and L may be set to L = 5, which results in M = 2L - 1 = 2×5 - 1 = 16.

[0145] For the shortest sequences, in the case of the PM-PHY with length N = 64, Gold sequences with +1 added (so-called "Gold+1") are used because they provide a simple yet effective technique for generating a set of orthogonal sequences with high bandwidth. The following steps may be taken. 1. A Gold sequence of length N = 63 requires a generating polynomial of degree r = 6. For degree r = 6, there are seven possible polynomials, three of which are primitive and can be used for Gold sequence generation. These three polynomials are listed below and can be used to generate three sets of N + 2 = 65 Gold sequences. x 6 +x + 1 x 6 +x 5 +x 2 +x + x 6 +x 5 +x 3 +x 2 +1 2. To make the generated sequences orthogonal and balanced, 1 is added. 3. The sequences are checked for their balance, and the unbalanced sequences are selected. Since there are 16 unbalanced sequences for each set, 65 - 16 = 49 sequences remain for each set. 4. The sequences are grouped to form 16 required sets. From the first 2 sets of the Gold sequences, 9 of the last sequences are discarded so that the remaining sequences can each form (49 - 9) / 8 = 5 orthogonal sets. From the last set of the Gold sequences, only the very last sequence is discarded so that that set can form the remaining (49 - 1) / 8 = 6 orthogonal sets for the VSF sequences. An example of the resulting sequences can be combined using the method described above to form longer sequences up to N = 1024, and obtain S 1024,0 ~S 1024,0 in this way.

[0146] Aspect The aspects of the above example are resumed here and integrated with other features. Note that the text within the angle brackets is optional in the following aspects. The symbols are shown without indices. The transmitter / receiver can preferably be a transmitter (e.g., an optical transmitter or another wireless or wired transmitter), but it can also be another wireless transmitter / receiver (as above) or a wired transmitter. When referring to "bit rate", it is also possible to generalize to "symbol rate", for example according to a specific modulation.

[0147] According to one aspect, a transmitter (e.g., an optical transmitter or another wireless or wired transmitter) [either a relay or a mobile device] is provided, and the transmitter is [e.g., at a first data rate] configured to selectively transmit a first pilot sequence, or [e.g., at a second data rate higher than the first data rate] a second pilot sequence in this way. The first pilot sequence [AAAA / ACAC ACAC] includes a plurality of [e.g., equal / different] symbols [the symbols include a part of one bit of the first pilot sequence or a part of more bits of the first pilot sequence], The second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD] includes the symbols [4-bit A / 4-bit 'A' and 4-bit 'C'] of the first pilot sequence [AAAA / ACAC ACAC], and one or more additional symbols [e.g., a part of one or more bits, e.g., 4-bit C / 4-bit B and 4-bit D] are [e.g., repeatedly] inserted [e.g., periodically and / or alternately] between the symbols of the first pilot sequence [the symbols of the first pilot sequence may be different from the symbols of the second pilot sequence] [each symbol may be a code or a part of a code, but the definition of claim 1 is open for each sequence obtained as a plurality of consecutive codes or parts of codes].

[0148] The transmitter, the first pilot sequence [AAAA] represents a first code, the second pilot sequence [ACAC ACAC] is, a first set of equally spaced symbols [A A A A] representing the first code [AAAA], and a second set of equally spaced symbols [C C C C] representing the second code [CCCC] and may include. It seems to be like this.

[0149] The transmitter, the first pilot sequence [ACAC ACAC] is, a first set of equally spaced symbols [A A A A] representing the first code [AAAA], and a second set of equally spaced symbols representing the second code [CCCC] [C C C C] and includes, The second pilot sequence [ABCD ABCD ABCD ABCD] is the first set [A A A A] of equidistant symbols representing the first code sequence [AAAA], and the second set [C C C C] of equidistant symbols representing the second code sequence [CCCC] and includes the second pilot sequence also includes a further set [B B B B but also D D D D] of equidistant symbols representing the third code [BBBB, DDDD] and may be like that.

[0150] The transmitter in the first pilot sequence [AAAA / ACAC ACAC], a plurality of [e.g., equal / different] symbols [4-bit A / 4-bit A and 4-bit C] are arranged according to a regular time base, and / or in the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], the symbols [e.g., 4-bit A / 4-bit A and 4-bit C] of the first pilot sequence and further symbols [4-bit C / 4-bit B and 4-bit D] inserted between the symbols of the first pilot sequence are arranged according to a regular time base. and may be like that.

[0151] The transmitter in the first pilot sequence [AAAA / ACAC ACAC], all symbols [4-bit A / 4-bit A and 4-bit C] have the same time length relative to each other, [e.g., because they are bits of the same length] and may be like that.

[0152] The transmitter In the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], the symbols of the first pilot sequence [AAAA / ACAC ACAC], [4-bit A / 4-bit A and 4-bit C], have the same time duration relative to each other [e.g., since they are bits of the same length]. It may seem so.

[0153] The transmitter In the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], the symbols of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], [4-bit C / 4-bit B and 4-bit D], have the same time duration relative to each other [e.g., since they are bits of the same length]. It may seem so.

[0154] The transmitter In the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], the symbols of the first pilot sequence [AAAA / ACAC ACAC], [4-bit A / 4-bit A and 4-bit C], and the symbols of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], [4-bit C / 4-bit B and 4-bit D], have the same time duration relative to each other [e.g., since they are bits of the same length]. It may seem so.

[0155] The transmitter The sum of the time durations of the symbols of the first pilot sequence [AAAA / ACAC ACAC] is the same as the sum of the time durations of the symbols of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], and / or The second [higher] data rate is a multiple of the first [lower] data rate according to an integer factor [e.g., a power of 2], and / or The length of the bit - unit data encoded within the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD] is a multiple of the length of the bit - unit data encoded within the first pilot sequence [AAAA / ACAC ACAC] according to, for example, an integer factor that is a power of 2. It may seem so.

[0156] The transmitter The bit rate of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD] is a multiple of the bit rate of the first pilot sequence [AAAA / ACAC ACAC] according to, for example, an integer factor that is a power of 2. It may seem so.

[0157] The transmitter The symbols of the first pilot sequence [AAAA / ACAC ACAC] represent a first code obtained from a set of orthogonal codes, deterministically or otherwise. The symbols of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD] represent at least one second code obtained from a set of orthogonal codes, deterministically or otherwise. It may seem so.

[0158] The transmitter The first pilot sequence represents a first code obtained from a set of codes (preferably orthogonal). The first set of equally - spaced bits of the second pilot sequence represents the first code. [The second set of equally - spaced bits of the second pilot sequence, which does not overlap with the first set of equally - spaced bits of the second pilot sequence and / or may be interleaved with respect to the first set of equally - spaced bits and / or may include the same bit interval as the first set of equally - spaced bits] represents a second code obtained from a set of codes (preferably orthogonal). It may seem so.

[0159] The transmitter A first set of equally spaced bits of the first pilot sequence represents a first code obtained from a set of [preferably orthogonal] codes, A second set of equally spaced bits of the first pilot sequence represents a second code obtained from a set of [preferably orthogonal] codes; A first set of equally spaced bits of the second pilot sequence represents the first code, A second set of equally spaced bits of the second pilot sequence represents the second code, A third set of equally spaced bits of the second pilot sequence [which does not overlap with the first set of equally spaced bits and the second set of equally spaced bits of the second pilot sequence, and / or may be preferably interleaved with respect to the first set of equally spaced bits and the second set of equally spaced bits, and / or may preferably include the same bit interval as the first set of equally spaced bits and the second set of equally spaced bits] represents a third code obtained from a set of [preferably orthogonal] codes It may seem so.

[0160] The transmitter Accordingly, each code of the set of orthogonal codes The number of 1s, The number of 0s The codes of the set of orthogonal codes are selected so as to enjoy a "balanced characteristic" or "substantially balanced characteristic" having a ratio between The ratio is 1 in the case of "balanced characteristic" and between a first threshold and a second threshold in the case of "substantially balanced characteristic" It may seem so.

[0161] The transmitter The codes of the set of orthogonal codes are selected so that each code of the set of orthogonal codes enjoys an autocorrelation characteristic having an autocorrelation peak of 30% or less of the main peak accordingly. It may seem so.

[0162] The transmitter For each pair of codes in the set of orthogonal codes, the codes in the set of orthogonal codes are selected such that the normalized cross-correlation between the two codes of the code pair conforms to a cross-correlation characteristic where the normalized cross-correlation is between -0.2 and +0.2. It may seem so.

[0163] The transmitter Transmits the first pilot sequence or the second pilot sequence using PAM [Pulse Amplitude Modulation] modulation. It may seem so.

[0164] The transmitter The first pilot sequence and the second pilot sequence are modulated according to PAM-2 [Pulse Amplitude Modulation] modulation [for example, each symbol is represented by the emission of light at a predetermined wavelength during a predetermined time slot if it is 1, and represented by the absence of emission during a predetermined time slot if it is 0, and vice versa]. It may seem so.

[0165] The transmitter may be configured to receive signaling [for example, wireless signaling in the case of a mobile device, wired signaling in the case where the transmitter is a relay] from an adjuster and select the first pilot sequence or the second pilot signal based on the signaling.

[0166] The transmitter may be configured to select a bit rate based on the signaling.

[0167] The transmitter is configured to select which codes are interleaved within the currently used pilot sequence according to the bit rate information, and for a given [determined] number of codes to be interleaved within the currently used pilot sequence, to select which one or more codes from the codebook of codes are included in the currently used pilot sequence according to the transmitter identifier information [e.g., obtained from signaling] [e.g., selected from the first and the second].

[0168] The transmitter appears to store in the memory unit the symbols [4-bit A / 4-bit A and 4-bit C] of the first pilot sequence [AAAA / ACAC ACAC] and the symbols [4-bit C / 4-bit B and 4-bit D] of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD], The transmitter may be further configured to generate a first pilot sequence or a second pilot signal selected by interleaving the symbols [4-bit A / 4-bit A and 4-bit C] of the first pilot sequence [AAAA / ACAC ACAC] or the symbols [4-bit C / 4-bit B and 4-bit D] of the second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD].

[0169] The transmitter may be configured to detect the reception of a beacon signal, and after synchronizing with the beacon signal, transmit the first pilot sequence or the second pilot sequence.

[0170] The transmitter stores the second pilot sequence according to a transmission order that defines how the second pilot sequence is transmitted, The transmitter may be configured to obtain the first pilot sequence by selecting the symbols of the first pilot sequence and discarding the symbols of the second pilot sequence.

[0171] The transmitter may be configured to transmit multiple different first pilot sequences or different second pilot sequences within different [e.g., subsequent] fields of the pilot signal within the same pilot signal.

[0172] The transmitter may be configured to obtain signaling information indicating whether to select a first pilot sequence or a second pilot sequence.

[0173] The transmitter may be configured to provide P pilot sequence slot positions within the same pilot signal for transmitting P different first pilot sequences or second pilot sequences at the P pilot sequence slot positions, each of the P different first pilot sequences or second pilot sequences is obtained from a stored set having V different stored second pilot sequences, as a result, P*V possible combinations are implied between the P pilot sequence slot positions and the V different stored second pilot sequences, and the P*V possible combinations are enumerated in a predetermined order, The transmitter may be further configured to receive information regarding the P selected combinations from signaling among the P combinations associating the P selected first pilot sequences or second pilot sequences transmitted at the P pilot sequence slot positions.

[0174] It may be that the P*V possible combinations are enumerated according to a combination index, and the combination index of each of the P selected combinations is obtained from the signaled index.

[0175] It may be that the signaled index encodes a number between 0 and P*V.

[0176] The transmitter may be such that V different stored second pilot sequences are enumerated from 0 to V - 1 and P pilot sequence slot positions are enumerated from 0 to P - 1, and the P selected combinations are obtained by performing an integer division between the signaled index and P or V, such that each position is associated with a combination obtained from the integer result of the integer division and the remainder of the integer division.

[0177] The transmitter may be such that the signaling information indicating whether to select the first pilot sequence or the second pilot sequence is different from the signaled index.

[0178] The transmitter may be such that the signaled index is transparent to the selection between the first pilot sequence and the second pilot sequence.

[0179] The transmitter may be further configured to synchronize with another transmitter such that the transmitter and the further transmitter transmit interleaved pilot sequences. There is a device [regulator] for adjusting the transmission of the pilot sequence from at least one transmitter [either a relay or a mobile device] to at least one receiver [either a mobile device or a relay], and the regulator, for at least one transmitter, selects the first pilot sequence [AAAA / ACAC ACAC] [for example, at a first data rate], or selects the second pilot sequence [for example, at a second data rate higher than the first data rate] and is configured to do so, wherein the first pilot sequence [AAAA / ACAC ACAC] includes a plurality of [for example, equal / different] symbols [for example, 4-bit A / 4-bit A and 4-bit C] arranged repeatedly, The second pilot sequence [ACAC ACAC / ABCD ABCD ABCD ABCD] includes the symbols of the first pilot sequence [4-bit A / 4-bit A and 4-bit C], and one or more additional symbols [4-bit C / 4-bit B and 4-bit D] are inserted, [e.g., iteratively] between the symbols of the first pilot sequence [in some cases, the symbols of the first pilot sequence may be different from the symbols of the second pilot sequence][each symbol can be a code, but the definition is open for each sequence obtained as a plurality of consecutive codes].

[0180] The device may be further configured to assign at least one first code to a first transmitter and at least one second code orthogonal to the at least one first code to a second transmitter, such that the first sequence is obtained from at least one first code and the second sequence is obtained from at least one second code.

[0181] The device may be further configured to transmit a beacon signal to a first transmitter (350a) and a second transmitter (350b) such that the first transmitter (350a) and the second transmitter (350b) synchronize to the beacon signal.

[0182] The device may be configured to instruct the first transmitter (350a) and the second transmitter (350b) to transmit in an interleaved manner with respect to each other.

[0183] According to one aspect, a receiver [either a relay or a mobile device] for receiving the transmission of a pilot sequence from an optical transmitter [either a mobile device or a relay] is provided, The receiver is configured to evaluate the channel impulse response from a pilot sequence [ACAC ACAC] that is transmitted by a transmitter at a full data rate and includes a first reduced data rate sequence [AAAA] and a second reduced data rate sequence [CCCC] by sampling at a reduced data rate, and the receiver is configured to evaluate the channel impulse response using the first reduced data rate sequence [AAAA] or the second reduced data rate sequence [CCCC].

[0184] The receiver is configured to select one of a first reception mode by sampling at a reduced symbol rate and a second reception mode by sampling at a full symbol rate, the second reception mode in which the impulse response is evaluated using the pilot sequence [ACAC ACAC]. There may be cases where it is configured to select one of the reception modes.

[0185] Other implementations Implementations in hardware or software may be executed using a digital storage medium that stores electronically readable control signals, such as cloud storage, floppy disk, DVD, Blue-Ray, CD, ROM, PROM, EPROM, EEPROM, or flash memory, which cooperate (or are capable of cooperating) with a programmable computer system so that their respective methods are executed. Thus, the digital storage medium may be computer-readable. Some examples according to the present invention include a data carrier having electronically readable control signals capable of cooperating with a programmable computer system so that one of the methods described herein is executed. In general, an example of the present invention may be implemented as a computer program product having program code, and the program code serves to execute one of the methods when the computer program product is executed on a computer. The program code may be stored, for example, in a machine-readable carrier. Another example includes a computer program for executing one of the methods described herein, stored in a machine-readable carrier. In other words, an example of the method of the present invention is thus a computer program having program code for executing one of the methods described herein when the computer program is executed on a computer.

[0186] A further example of the method of the present invention is thus a data carrier (or digital storage medium or computer-readable medium) that records and includes a computer program for executing one of the methods described herein. A further example of the method of the present invention is thus a data stream or signal sequence representing a computer program for executing one of the methods described herein. The data stream or signal sequence may be configured to be transferred, for example, via a data communication connection, such as via the Internet. A further example includes processing means, such as a computer or a programmable logic device, configured or adapted to execute one of the methods described herein. A further example includes a computer installed with a computer program for executing one of the methods described herein.

[0187] In some examples, a programmable logic device (e.g., a field programmable gate array) may be used to execute some or all of the functions of the methods described herein. In some examples, the field programmable gate array can cooperate with a microprocessor to execute one of the methods described herein. In general, the method is preferably executed by any hardware device.

[0188] The above examples are merely illustrative of the principles of the present invention. It should be understood that modifications and variations of the configurations and details described herein will be apparent to those skilled in the art. Therefore, it is intended to be limited only by the claims of the near future, rather than by the specific details presented as examples and descriptions in this specification.

Claims

1. A transmitter configured to transmit a pilot signal including a pilot sequence, wherein the transmitter is configured to select the pilot sequence from among a plurality of pilot sequences (S Ａ , S ＡＣ ), and the plurality of pilot sequences include at least The first pilot sequence (S Ａ ) and The second pilot sequence (S ＡＣ ) and comprising, The first pilot sequence (S Ａ ) includes a plurality of symbols (A Ａ , A １ , A ２ , A ３ , A ４ ) of the first pilot sequence (S The second pilot sequence (S ＡＣ ) is the first pilot sequence (S Ａ ) the symbol (A １ , A ２ , A ３ , A ４ ) and the first pilot sequence (S Ａ ) the symbol (A １ , A ２ , A ３ , A ４ ) and the second pilot sequence (S ＡＣ ) further symbols (C １ , C ２ , C ３ , C ４ ) and wherein the transmitter is configured to The said first pilot sequence (S Ａ ) of the said symbol (A １ , A ２ , A ３ , A ４ ) includes at least one first set of symbols of equally spaced symbols, each first set of equally spaced symbols represents a respective first code, and said second pilot sequence (S ＡＣ ), said symbol (C １ , C ２ , C ３ , C ４ ) includes at least one second set of equally spaced symbols, and each second set of equally spaced symbols represents a respective second code different from each first code define, wherein the transmitter is configured to select each first code and each second code from the set of codes such that each code of a selected set of codes from the set of codes is orthogonal to at least one other non - selected code of the set of codes, wherein the transmitter is configured to transmit the first pilot sequence at a first symbol rate and to transmit the second pilot sequence at a second symbol rate that is a multiple of the first symbol rate according to a predetermined integer factor, wherein the time duration of the first pilot sequence is the same as the time duration of the second pilot sequence, wherein the sum of the number of symbols of at least one first set of equally - spaced symbols and the number of at least one second set of equally - spaced symbols is a multiple of the at least one first set of equally - spaced symbols according to the predetermined integer factor, and the predetermined integer factor is greater than 1, wherein the transmitter transmits a selected pilot sequence according to pulse - amplitude modulation (PAM). A transmitter.

2. The transmitter according to claim 1, wherein the plurality of pilot sequences includes at least one third pilot sequence, the third pilot sequence includes the symbols of the first pilot sequence and the symbols of the second pilot sequence, and one or more additional symbols are interleaved with the symbols of the first pilot sequence and the symbols of the second pilot sequence, such that the transmitter transmits the pilot sequence from at least the first pilot sequence, the second pilot sequence, and the third pilot sequence.

3. Within the selected pilot sequence, the plurality of symbols are arranged according to a regular time - base, Within the second pilot sequence, the symbols of the first pilot sequence and the additional symbols interleaved with the symbols of the first pilot sequence are arranged according to a regular time - base. The transmitter according to claim 1.

4. At least one first code represented by said at least one first set of equally spaced symbols, and at least one second code represented by said at least one second set of equally spaced symbols, when interleaved with each other, form a composite code orthogonal to an additional composite code formed by at least one first additional code orthogonal to said at least one first code and at least one second additional code orthogonal to said at least one second code, such that within said additional composite code, said at least one first additional code and said at least one second additional code are each interleaved with each other such that the positions of the entries of each first code and the entries of each first additional code correspond. The transmitter according to claim 1. **Claim 5** The transmitter includes or accesses a storage unit in which a plurality of codes are stored, and the codes are stored according to a format in which a plurality of codes are interleaved with other codes to form a composite code, such that the codes selected for said selected pilot sequence are obtained from the selected positions of the composite code. The transmitter further For each code used for each set of equally spaced symbols Which of the plurality of stored composite codes is selected, and The transmitter according to claim 1, configured to receive signaling from an adjuster indicating which shift the interleaved code selected within the selected composite code has in order to identify the set of equally spaced entries within the selected composite code from which the symbols of the selected sequence are obtained. **Claim 6** The transmitter includes or accesses a storage unit in which at least V different pilot sequences are stored, Configured to define P pilot sequence slot positions within the same pilot signal for transmitting P different selected pilot sequences, each of said P selected pilot sequences being transmitted at one of said P pilot sequence slot positions. ​ Each of the P selected pilot sequences is obtained from the at least V different stored pilot sequences, such that at least P*V possible combinations are implied between the P pilot sequence slot positions and the at least V different stored pilot sequences, and the at least P*V possible combinations are enumerated in a predetermined order. The transmitter is further configured to receive signaling that selects the P selected combinations that associate the P selected pilot sequences transmitted at each of the respective P pilot sequence slot positions. The at least P*V possible combinations are enumerated according to a combination index, and the combination index of each of the P selected combinations is obtained from the signaled index. The signaled index encodes a number between 0 and P*V−1. The transmitter according to claim 1, wherein the at least V different stored pilot sequences are enumerated from 0 to V−1, the P pilot sequence slot positions are enumerated from 0 to P−1, and the P selected combinations are obtained by performing an integer division between the signaled index and P or V, such that each position is associated with a combination obtained from the integer result of the integer division and the remainder of the integer division.

7. The transmitter according to claim 1, wherein each entry of each code of the set of codes encodes a binary value that is either one first binary value or one second binary value different from the first binary value.

8. The transmitter according to claim 1, wherein each code in the set of codes has a “balanced property” such that, for each code in the set of codes, the number of entries having a first logical value is the same as the number of any other logical value.

9. The transmitter according to claim 1, wherein the pulse amplitude modulation (PAM) is PAM-2 modulation.

10. The selected pilot sequence is modulated according to modulation such that each symbol is represented by physical emission at a predetermined wavelength for a predetermined time slot if it is the first binary value, or by the absence of emission for the predetermined time slot if it is the second binary value. The transmitter according to claim 1.

11. Detecting reception of a beacon signal, configured to transmit the selected pilot sequence or the second pilot sequence after synchronizing with the beacon signal, The transmitter according to claim 1.

12. The transmitter according to claim 1, wherein the transmitter is an optical transmitter.

13. The transmitter according to claim 1, wherein the transmitter is a radio frequency (RF) transmitter.

14. A method for transmitting a pilot signal including a pilot sequence selected from a plurality of pilot sequences including at least a first pilot sequence and a second pilot sequence, wherein the first pilot sequence includes a plurality of symbols of the first pilot sequence, the second pilot sequence includes the symbols of the first pilot sequence and further symbols of the second pilot sequence interleaved with the symbols of the first pilot sequence, the method comprising: each of the at least one first set of equally spaced symbols of the first pilot sequence represents a respective first code, and each of the at least one second set of equally spaced symbols of the second pilot sequence represents a respective second code different from each first code defining steps, the method comprising: selecting each first code and each second code from the set of codes such that each code of the selected set of codes from the set of codes is orthogonal to at least one other non-selected code of the set of codes, the method including transmitting the selected pilot sequence, the transmitting including transmitting the first pilot sequence at a first symbol rate and transmitting the second pilot sequence at a second symbol rate that is a multiple of the first symbol rate according to a predetermined integer factor, the time duration of the first pilot sequence being the same as the time duration of the second pilot sequence, The sum of the number of symbols of at least one first set of equally-spaced symbols and the number of at least one second set of equally-spaced symbols is a multiple of the at least one first set of equally-spaced symbols according to the predetermined integer coefficient, and the predetermined integer coefficient is greater than 1, The selected pilot sequence is transmitted according to pulse amplitude modulation (PAM). Method.

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