Devices and methods for generating improved preambles in a mobile network

Abstract

A wireless terminal device (110), e.g. a UE (110) is disclosed for communication with a wireless network device (120), e.g. a base station (120). The wireless terminal device (110) is configured to obtain a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cm of a point-wise multiplication of an original, i.e. legacy ZC sequence with a shaping sequence. Moreover, the wireless terminal device (110) is configured to generate an initial-access preamble based on the shaped ZC sequence and to transmit the preamble to the wireless network device (120). Furthermore, a correspondingly configured wireless network device (120) is disclosed. The initial-access preamble based on the shaped ZC sequence may result in less leakage and, thus, better performance.

Description

[0001] DEVICES AND METHODS FOR GENERATING IMPROVED PREAMBLES IN A MOBILE NETWORK

[0002] TECHNICAL FIELD

[0003] The present invention relates to wireless communications. More specifically, the present invention relates to devices and methods for generating improved preambles in a mobile network, in particular a 3rd Generation Partnership Project (3GPP) mobile network.

[0004] BACKGROUND

[0005] Physical random-access channel (PRACH) is an essential part of wireless communication systems, such as 5G new radio (NR), as it is used by terminal devices to transmit preambles needed for establishing the initial access to the network. Zadoff-Chu, ZC, sequences are chirp-like sequences used for generating those initial-access preambles in 4G LIE and 5G systems, as defined in 3GPP TS 38.213, “Physical layer procedures for control”. In each cell area, the ZC sequences to be used for initial access are generated by the terminal devices using a root value signaled in a downlink message by the base station, i.e. the network device of the cell so that the same root value is used by all the terminal devices of one cell. Nonetheless, the preambles from different terminal devices are still distinguishable by the base station because each terminal device applies a cyclic shift to the ZC sequence with a cyclic shift value that is randomly selected from a set of possible shift values also signaled by the base station.

[0006] However, even if two terminal devices transmit their ZC preambles with different cyclic shifts, it still can happen that the terminal device whose preamble signal is weaker, for instance, because the terminal device is located near the cell edge, is eclipsed by the stronger signal of the preamble of a terminal device located closer to the cell center. This so-called near-far effect happens because of the known issue of leakage between the different cyclic shifts of a ZC sequence when received after passing through the wireless channel. Due to this effect, the initial access attempt of some cell edge terminal devices might fail leading to the need for retransmitting their preambles and hence causing additional overhead.

[0007] SUMMARY

[0008] It is an objective to provide improved devices and methods for generating improved preambles based on ZC sequences in a mobile network, in particular a 3GPP mobile network.

[0009] The foregoing and other objectives are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0010] According to a first aspect a wireless terminal device is provided for communication with a wireless network device of a wireless communication system. In an implementation form, the wireless communication system may be a 3GPP mobile network, in particular a 3GPP 5G or another future mobile network. In an implementation form, the wireless terminal device may be a user equipment, UE, and the wireless network device may be a base station, such as a gNB, of a mobile network. The wireless terminal device according to the first aspect is configured to obtain a shaped, e.g. attenuated Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a point-wise multiplication of an original ZC sequence (also referred to as legacy ZC sequence herein) with a shaping sequence. Moreover, the wireless terminal device according to the first aspect is configured to generate an initial-access preamble based on the shaped ZC sequence and to transmit the preamble to a wireless network device. The initial-access preamble based on the shaped ZC sequence may result in less leakage and, thus, better performance. In a further possible implementation form, the wireless terminal device according to the first aspect is configured to generate the shaped ZC sequence based on the one or more ZC sequence parameters. Thus, the wireless terminal device according to the first aspect may efficiently generate the shaped ZC sequence on the fly.

[0011] In a further possible implementation form, the one or more ZC sequence parameters comprise one or more possible index values and the wireless terminal device is configured to select one index value of the one or more possible index values for determining the cyclic shift value Cm. In an implementation form, the wireless terminal device may be configured to randomly select one index value from the possible index values for determining the cyclic shift value Cm. This allows to efficiently make sure that every wireless terminal in a cell is using a different cyclic shift value Cm.

[0012] In a further possible implementation form, the one or more ZC sequence parameters comprise: a root value, a sequence length, and / or a number of ZC sequence repetitions per preamble. The number of ZC sequence repetitions per preambles defines how many times the shaped ZC sequence is to be concatenated for generating the preamble.

[0013] In a further possible implementation form, the wireless terminal device according to the first aspect is configured to generate the shaped ZC sequence xu m| n | based on the following equation: xu,m [n] = Xu[(n + Cm) mod / Vzc]wu,m[n], wherein wu m[n] = wu[(n + Cm) mod 1VZC] denotes the cyclically shifted shaping sequence, wudenotes the shaping sequence, and Nzcdenotes the sequence length. Based on this equation, the wireless terminal device according to the first aspect may efficiently determine the shaped ZC sequence.

[0014] In a further possible implementation form, the wireless terminal device according to the first aspect is configured to generate the initial-access preamble based on the shaped ZC sequence by concatenating, i.e. repeating at least once the shaped ZC sequence with the shaped sequence and / or a portion of the shaped ZC sequence. This allows the wireless terminal device according to the first aspect to efficiently generate the preamble, when the preamble is larger than the shaped ZC sequence.

[0015] In a further possible implementation form, the wireless terminal device according to the first aspect is configured to generate the initial-access preamble by adding a preamble cyclic prefix and a preamble zero suffix to the concatenation of the shaped ZC sequence.

[0016] In a further possible implementation form, the wireless terminal device according to the first aspect transmits the preamble on a physical random-access channel, PRACH, of the wireless communications system to the wireless network device.

[0017] In a further possible implementation form, the wireless terminal device according to the first aspect is configured to measure a reference signal received power, RSRP, value of a reference signal from the wireless network device, and to determine the shaping sequence by selecting the shaping sequence from a plurality of different shaping sequences based on the measured RSRP value of the reference signal from the wireless network device. This allows the wireless terminal device according to the first aspect to select the amount of shaping depending on the measured RSRP value of the reference signal from the wireless network device, for instance, select a stronger shaping for a larger measured RSRP value of the reference signal and a weaker shaping for a smaller measured RSRP value of the reference signal.

[0018] In a further possible implementation form, the wireless terminal device according to the first aspect is configured to receive one or more RSRP threshold values from the wireless network device and the wireless terminal device according to the first aspect is configured to select the shaping sequence from the plurality of different shaping sequences based on a comparison between the measured RSRP value of the reference signal from the wireless network device and the one or more RSRP threshold values. This allows the wireless terminal device according to the first aspect to efficiently select the amount of shaping applied for generating the shaped ZC sequence.

[0019] In a further possible implementation form, the plurality of different shaping sequences comprises a plurality of concatenations of a shorter basis shaping sequence, wherein each basis shaping sequence has a different shape. For instance, a first shaping sequence of the plurality of different shaping sequences may comprise a plurality of concatenations of a first basis shaping sequence with a first pulse size and a second shaping sequence may comprise a plurality of concatenations of a second basis shaping sequence with a second pulse size different from the first pulse size.

[0020] In a further possible implementation form, the shaping sequence provides attenuation of the original ZC sequence at one or more of the following points tu qof the original ZC sequence: wherein u denotes a root value, q denotes an integer, Ncdenotes the size of the ZC sequence, and At denotes an inverse of a bandwidth.

[0021] According to a second aspect a method of operating a wireless terminal device is provided. The method according to the second aspect comprises: obtaining a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a point-wise multiplication of an original ZC sequence with a shaping sequence; generating an initial-access preamble based on the shaped ZC sequence; and transmitting the preamble to a wireless network device.

[0022] The initial-access preamble based on the shaped ZC sequence may lead to less leakage. The method according to the second aspect can be performed by the wireless terminal device according to the first aspect. Thus, further features of the method according to the second aspect result directly from the functionality of the wireless terminal device according to the first aspect as well as its different implementation forms described above and below.

[0023] According to a third aspect a wireless network device is provided for providing network access for a wireless terminal device in a wireless communication system. In an embodiment, the wireless network device may be a base station, such as a gNB, and the wireless terminal device may be a user equipment, UE, of a mobile network. The wireless network device according to the third aspect is configured to receive an initial-access preamble from a wireless terminal device, wherein the preamble is based on a shaped Zadoff-Chu, ZC, sequence and wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a point-wise multiplication of an original ZC sequence with a shaping sequence. The initial-access preamble based on the shaped ZC sequence may lead to less leakage.

[0024] In a further possible implementation form, the wireless network device according to the third aspect is configured to transmit one or more ZC sequence parameters to the wireless terminal device, wherein the shaped ZC sequence is based on the one or more ZC sequence parameters. In a further possible implementation form, the one or more ZC sequence parameters comprise one or more possible index values for the wireless terminal device to select one index value of the one or more possible index values for determining a cyclic shift value Cm.

[0025] In a further possible implementation form, the one or more ZC sequence parameters comprise: a root value, a sequence length, and / or a number of ZC sequence repetitions per preamble.

[0026] In a further possible implementation form, the preamble is based on a concatenation of the shaped ZC sequence at least once with the shaped sequence and / or a portion of the shaped ZC sequence.

[0027] In a further possible implementation form, the initial-access preamble further comprises a preamble cyclic prefix and a preamble zero suffix.

[0028] In a further possible implementation form, the wireless network device is configured to receive the preamble on a physical random-access channel, PRACH, of the wireless communications system from the wireless terminal device.

[0029] In a further possible implementation form, the wireless network device is configured to transmit a reference signal to the wireless terminal device for allowing the wireless terminal device to measure a reference signal received power, RSRP, value of the reference signal and to determine the shaping sequence by selecting the shaping sequence from a plurality of different shaping sequences based on the measured RSRP value of the reference signal. As already mentioned above, in an implementation form, the wireless communication system may be a 3GPP mobile network and the RSRP value may be the standardized RSRP value.

[0030] In a further possible implementation form, the wireless network device is configured to transmit one or more RSRP threshold values to the wireless terminal device for allowing the wireless terminal device to select the shaping sequence from the plurality of different shaping sequences based on a comparison between the measured RSRP value of the reference signal and the one or more RSRP threshold values.

[0031] In a further possible implementation form, the plurality of different shaping sequences comprises a plurality of concatenations of a shorter basis shaping sequence, wherein each basis shaping sequence has a different shape.

[0032] In a further possible implementation form, the shaping sequence provides attenuation of the original ZC sequence at one or more of the following points tu qof the original ZC sequence: wherein u denotes a root value, q denotes an integer, Ncdenotes the size of the ZC sequence, and At denotes an inverse of a bandwidth.

[0033] According to a fourth aspect a method of operating a wireless network device is provided. The method according to the fourth aspect comprises: receiving an initial-access preamble from a wireless terminal device, wherein the preamble is based on a shaped Zadoff- Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a pointwise multiplication of an original ZC sequence with a shaping sequence. The initial-access preamble based on the shaped ZC sequence may lead to less leakage. The method according to the fourth aspect can be performed by the wireless network device according to the third aspect. Thus, further features of the method according to the fourth aspect result directly from the functionality of the wireless network device according to the third aspect as well as its different implementation forms described above and below.

[0034] According to a fifth aspect a computer program product is provided, comprising program code which causes a computer or a processor to perform the method according to the second aspect or the method according to the fourth aspect, when the program code is executed by the computer or the processor.

[0035] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the following, embodiments of the present disclosure are described in more detail with reference to the attached figures and drawings, in which:

[0038] Fig. 1 is a schematic diagram showing a wireless communication system, including a plurality of wireless terminal devices according to an embodiment in communication with a wireless network device according to an embodiment;

[0039] Fig. 2 is a diagram illustrating different stages implemented by a wireless terminal device according to an embodiment for generating an improved ZC sequence and preamble;

[0040] Fig. 3 is a schematic diagram illustrating different zones in the vicinity of a wireless network device according to an embodiment used by a wireless terminal device according to an embodiment for selecting different shaping sequences;

[0041] Fig. 4 is a diagram illustrating an original ZC sequence as well as a first shaping sequence and a second shaping sequence implemented by a wireless terminal device according to an embodiment for generating a shaped ZC sequence;

[0042] Fig. 5 shows a flow diagram illustrating steps of a method of operating a wireless terminal device according to an embodiment; and

[0043] Fig. 6 shows a flow diagram illustrating steps of a method of operating a wireless network device according to an embodiment.

[0044] In the following, identical reference signs refer to identical or at least functionally equivalent features.

[0045] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] In the following description, reference is made to the accompanying figures, which form part of the disclosure, and which show, by way of illustration, specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It is understood that embodiments of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. For instance, it is to be understood that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0047] Figure 1 shows an exemplary wireless communication network 100, in particular a 3GPP mobile network 100, including a wireless network device 120, e.g. a base station 120, configured to provide network access to a plurality of wireless terminal devices 110, e.g. UEs 110. As illustrated in figure 1 both the wireless network device 120, e.g. base station 120 and the wireless terminal devices 110, e.g. UEs may comprise a plurality of antennas, for instance, for beamforming. Moreover, in the embodiment shown in figure 1, each wireless terminal device 110, e.g. UE 110 comprises a transmit (Tx) unit 111 for generating and transmitting transmit signals and a receive (Rx) unit 113 for receiving and processing receive signals. Each wireless terminal device 110, e.g. UE 110 may comprise further processing circuitry for implementing at least some of the functionality disclosed herein. The processing circuitry may be implemented in hardware and / or software. The hardware may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or one or more general- purpose processors. Moreover, each wireless terminal device 110, e.g. UE 110 may comprise a memory configured to store executable program code which, when executed by the processing circuitry, causes the wireless terminal device 110, e.g. UE 110 to perform the functions and operations described herein.

[0048] Likewise, the wireless network device 120, e.g. base station 120 may comprise processing circuitry for implementing at least some of the functionality disclosed herein. The processing circuitry may be implemented in hardware and / or software. The hardware may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or one or more general-purpose processors. Moreover, the wireless network device 120, e.g. base station 120 may comprise a memory configured to store executable program code which, when executed by the processing circuitry, causes the wireless network device 120, e.g. base station 120 to perform the functions and operations described herein.

[0049] As will be described in more detail in the following under further reference to figure 2, each wireless terminal device 110, e.g. UE 110 is configured to obtain a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence. Moreover, each wireless terminal device 110, e.g. UE 110 is configured to generate an initial-access preamble based on the shaped ZC sequence and to transmit the initial-access preamble to the wireless network device 120, e.g. base station. In an embodiment, the wireless terminal device 110, e.g. UE 110 is configured to transmit the initial-access preamble based on the shaped ZC sequence on a physical random-access channel, PRACH, of the wireless communications system 100 to the wireless network device 120, e.g. base station 120. In an embodiment, the original ZC sequence xuwith root value u and length / Vzcmay be represented in the following way:

[0050] In an embodiment, the wireless terminal device 110, e.g. UE 110 is configured to obtain the shaped ZC sequence based on the original ZC sequence by generating the shaped ZC sequence based on the original ZC sequence on the fly or by retrieving the shaped ZC sequence based on the original ZC sequence from memory. xu, m M = xu[(n + Cm) mod lVzc]wu.m[n], wherein wu m[n] = wu[(n + Cm) mod N7C] denotes the cyclically shifted shaping sequence.

[0051] In an embodiment, the shaping sequence provides attenuation of the original ZC sequence at one or more of the following points tu qof the original ZC sequence: wherein u denotes the root value, q denotes an integer, Ncdenotes the size of the ZC sequence, and At denotes an inverse of a bandwidth, such as the bandwidth of the PRACH used for transmitting the initial-access preamble. Attenuation at one or more of these points tu qis advantageous, because the oversampled original ZC sequence exhibits large variations at these points. These critical points tu qhave been found by analyzing the instantaneous phase of the continuous time version of the original ZC sequence xuand identifying the discontinuities. As will be appreciated, these high variations matter in presence of a wireless channel with fractional-valued path delays leading to leakage during initial access. In order to minimize or at least mitigate this leakage according to embodiments disclosed herein the shaping sequence used for generating the shaped ZC sequence provides attenuation of the original ZC sequence at one or more of the critical points tu q.

[0052] In an embodiment, a trade-off between peak-to-average power (PAPR) performance and leakage rejection performance may be implemented by the wireless terminal device 110, e.g. UE 110 and the wireless network device 120, e.g. base station 120. Since in an embodiment a wireless terminal device, e.g. UE close to the cell center may generate during preamble detection at the base station the most leakage for other wireless terminal devices, e.g. UEs close to the cell edge, and they have the least need for good PAPR so they should use a leakage attenuation sequence that yields significant leakage reduction no matter its effect on PAPR. While cell edge terminals, who need the best possible PAPR performance because they need to transmit their preambles with large power to compensate for their large path loss, should use a leakage reduction sequence having the least effect on PAPR (and hence possibly the least leakage reduction).

[0053] As illustrated in figure 3, in an embodiment the wireless terminal device 110, e.g. UE 110 is configured to measure a Reference Signal Received Power, RSRP, of one or more downlink reference signals and to compare the measured RSRP value with one or more RSRP threshold values broadcasted by the wireless network device 120, e.g. base station 120. This allows the wireless terminal device 110, e.g. UE 110 to determine whether it is in the first cell zone 300a, the second cell zone 300b or the n-th cell zone 300n and, thus, the best suited shaping sequence. In an embodiment, each of the RSRP threshold values broadcasted by the wireless network device 120, e.g. base station 120 may be coupled with a certain choice of the shaping sequence for leakage attenuation defining a certain PAPR-leakage trade-off level.

[0054] Figure 4 is a diagram illustrating an original ZC sequence (indicated as curve A) as well as a first shaping sequence and a second shaping sequence (indicated as curves B and C) implemented by the wireless terminal device 110, e.g. UE 110 according to an embodiment for generating the shaped ZC sequence. As will be appreciated, in the example shown in figure 4, the first shaping sequence (indicated as curve B) provides a stronger attenuation of the original ZC sequence than the second shaping sequence (indicated as curve C).

[0055] In an embodiment, the wireless terminal device 110, e.g. UE 110 is configured to receive from the wireless network device 120, e.g. base station 120 one or more ZC sequence parameters, in particular ZC codebook parameters for generating the shaped ZC sequence. In an embodiment, the one or more ZC sequence parameters may include, for instance, the root value, the sequence length, the index set of allowed cyclic shifts, and the number of sequence repetitions per preamble. As already described above, the wireless terminal device 110, e.g. UE 110 may further receive from the wireless network device 120, e.g. base station 120 one or more RSRP threshold values as well as one or more sub-pulse shape indicators for generating the shaping sequence. In an embodiment, the wireless network device 120, e.g. base station 120 may transmit the one or more RSRP threshold values, for instance, by means of a radio resource control (RCC) message.

[0056] In an embodiment, the wireless terminal device 110, e.g. UE 110 is configured to measure the RSRP level and compare the measured RSRP value with the signaled RSRP threshold values to select a sub-pulse shape based on the sub-pulse shape indicator corresponding (in the signaled pairs) to the RSRP threshold value that is the closest to the measured RSRP level, for instance, the sub-pulse shape illustrated in the top most diagram of figure 2. For this embodiment the wireless terminal device 110, e.g. UE 110 is further configured to generate the shaping sequence for leakage attenuation by concatenating the thus obtained sub-pulse shape a number of times based on the root value, as illustrated in the second to top diagram of figure 2. Moreover, the wireless terminal device 110, e.g. UE 110 is further configured to apply a cyclic shift with the selected cyclic shift value to the concatenation of the sub pulsed, as illustrated in the second to bottom diagram of figure 2. As already described above, the wireless terminal device 110, e.g. UE 110 is further configured to generate the shaped ZC sequence as the pointwise product of the original ZC sequence and the shaping sequence and applying the selected cyclic shift to the resulting sequence, as illustrated in the bottom most diagram of figure 2. The initial-access preamble may be generated by repeating the ZC sequence a number of times as indicated by the wireless network device 120, e.g. base station 120. More specifically, in an embodiment, the wireless terminal device 110, e.g. UE may be configured to implement the following steps for generating the initial-access preamble based on the shaped ZC sequence:

[0057] Figure 5 shows a flow diagram illustrating steps of a method 500 of operating the wireless terminal device 110, e.g. the UE 110. The method 500 comprises a step 501 of obtaining a shaped ZC sequence, wherein, as described above in detail, the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence. The method 500 further comprises a step 503 of generating a preamble based on the shaped ZC sequence and a step 505 of transmitting the preamble to the wireless network device 120.

[0058] Figure 6 shows a flow diagram illustrating steps of a method 500 of operating the wireless network device 120, e.g. the base station 120. The method 600 comprises a step 601 of receiving a preamble from the wireless terminal device 110, e.g. UE 110, wherein the preamble is based on a shaped ZC sequence and wherein, as described above in detail, the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence.

[0059] The person skilled in the art will understand that the "blocks" ("units") of the various figures (method and apparatus) represent or describe functionalities of embodiments of the present disclosure (rather than necessarily individual "units" in hardware or software) and thus describe equally functions or features of apparatus embodiments as well as method embodiments (unit = step). In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described embodiment of an apparatus is merely exemplary. For example, the unit division is merely logical function division and may be another division in an actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

[0060] The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

[0061] In addition, functional units in the embodiments of the invention may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit.

Claims

1. CLAIMS1. A wireless terminal device (110) configured to: obtain a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence; generate a preamble based on the shaped ZC sequence; and transmit the preamble to a wireless network device.

2. The wireless terminal device (110) of claim 1, wherein the wireless terminal device (110) is configured to receive one or more ZC sequence parameters from the wireless network device (120) and to obtain the shaped ZC sequence based on the one or more ZC sequence parameters.

3. The wireless terminal device (110) of claim 2, wherein the wireless terminal device (110) is configured to generate the shaped ZC sequence based on the one or more ZC sequence parameters.

4. The wireless terminal device (110) of claim 3, wherein the one or more ZC sequence parameters comprise one or more possible index values and wherein the wireless terminal device (110) is configured to select one index value of the one or more possible index values for determining the cyclic shift value Cm.

5. The wireless terminal device (110) of any one of claims 2 to 4, wherein the one or more ZC sequence parameters comprise: a root value, a sequence length, and / or a number of ZC sequence repetitions per preamble.

6. The wireless terminal device (110) of any one of claims 3 to 5, wherein the wireless terminal device (110) is configured to generate the shaped ZC sequence based on the one or more ZC sequence parameters based on the following equation: xu,m[n] = „[( + Cm) mod / Vzc]wu,m[n], wherein wu m[n] = wu[(n + Cm) mod N7C] denotes the cyclically shifted shaping sequence, wudenotes the shaping sequence, and Nzcdenotes the sequence length.

7. The wireless terminal device (110) of any one of the preceding claims, wherein the wireless terminal device (110) is configured to generate the preamble based on the shaped ZC sequence by concatenating at least once the shaped ZC sequence with the shaped sequence and / or a portion of the shaped ZC sequence.

8. The wireless terminal device (110) of claim 7, wherein wireless terminal device (110) is configured to generate the preamble by adding a preamble cyclic prefix and a preamble zero suffix to the concatenation of the shaped ZC sequence.

9. The wireless terminal device (110) of any one of the preceding claims, wherein the wireless terminal device (110) transmits the preamble on a physical random-access channel, PRACH, of a wireless communications system (100) to the wireless network device (120).

10. The wireless terminal device (110) of any one of the preceding claims, wherein the wireless terminal device (110) is configured to measure a reference signal received power, RSRP, value of a reference signal from the wireless network device (120), and to determine the shaping sequence by selecting the shaping sequence from a plurality of shaping sequences based on the RSRP value of the reference signal from the wireless network device (120).

11. The wireless terminal device (110) of claim 10, wherein the wireless terminal device (110) is configured to receive one or more RSRP threshold values from the wireless network device (120) and wherein the wireless terminal device (110) is configured to select the shaping sequence from the plurality of shaping sequences based on a comparison between the RSRP value of the reference signal from the wireless network device (120) and the one or more RSRP threshold values.

12. The wireless terminal device (110) of claim 10 or 11, wherein the plurality of shaping sequences comprises a plurality of concatenations of a basis shaping sequence, wherein each basis shaping sequence has a different shape.

13. The wireless terminal device (110) of any one of the preceding claims, wherein the shaping sequence provides attenuation of the original ZC sequence at one or more of the following points tu qof the original ZC sequence:wherein u denotes a root value, q denotes an integer, Ncdenotes the size of the ZC sequence, and At denotes an inverse of a bandwidth.

14. A method (500) of operating a wireless terminal device (110), wherein the method (500) comprises: obtaining (501) a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence; generating (503) a preamble based on the shaped ZC sequence; and transmitting (505) the preamble to a wireless network device (120).

15. A wireless network device (120) configured to: receive a preamble from a wireless terminal device (110), wherein the preamble is based on a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence.

16. The wireless network device (120) of claim 15, wherein the wireless network device (120) is configured to transmit one or more ZC sequence parameters to the wireless terminal device (110) and wherein the shaped ZC sequence is based on the one or more ZC sequence parameters.

17. The wireless network device (120) of claim 16, wherein the one or more ZC sequence parameters comprise one or more possible index values for the wireless terminal device (110) to select one index value of the one or more possible index values for determining a cyclic shift value Cm.

18. The wireless network device (120) of claims 16 or 17, wherein the one or more ZC sequence parameters comprise: a root value, a sequence length, and / or a number of ZC sequence repetitions per preamble.

19. The wireless network device (120) of claim 18, wherein the shaped ZC sequence is based on the following equation: xu,m[n] = „[( + Cm) mod / Vzc]wu,m[n], wherein wu m[n] = wu[(n + Cm) mod N7C] denotes the cyclically shifted shaping sequence, wudenotes the shaping sequence, and Nzcdenotes the sequence length.

20. The wireless network device (120) of any one of claims 15 to 19, wherein the preamble is based on a concatenation of the shaped ZC sequence at least once with the shaped sequence and / or a portion of the shaped ZC sequence.

21. The wireless network device (120) of claim 20, wherein the preamble further comprises a preamble cyclic prefix and a preamble zero suffix.

22. The wireless network device (120) of any one of claims 15 to 21, wherein the wireless network device (120) is configured to receive the preamble on a physical random-access channel, PRACH, of a wireless communications system (100) from the wireless terminal device (110).

23. The wireless network device (120) of any one of claims 15 to 22, wherein the wireless network device (120) is configured to transmit a reference signal to the wireless terminal device (110) for allowing the wireless terminal device (110) to measure a reference signal received power, RSRP, value of the reference signal and to determine the shaping sequence by selecting the shaping sequence from a plurality of shaping sequences based on the RSRP value of the reference signal.

24. The wireless network device (120) of claim 23, wherein the wireless network device (120) is configured to transmit one or more RSRP threshold values to the wireless terminal device (110) for allowing the wireless terminal device (110) to select the shaping sequence from the plurality of shaping sequences based on a comparison between the RSRP value of the reference signal and the one or more RSRP threshold values.

25. The wireless network device (120) of claim 23 or 24, wherein the plurality of shaping sequences comprises a plurality of concatenations of a basis shaping sequence, wherein each basis shaping sequence has a different shape.

26. The wireless network device (120) of any one of claims 15 to 25, wherein the shaping sequence provides attenuation of the original ZC sequence at one or more of the following points tu qof the original ZC sequence:wherein u denotes a root value, q denotes an integer, Ncdenotes the size of the ZC sequence, and At denotes an inverse of a bandwidth.

27. A method (600) of operating a wireless network device (120), wherein the method (600) comprises: receiving (601) a preamble from a wireless terminal device (110), wherein the preamble is based on a shaped Zadoff-Chu, ZC, sequence, wherein the shaped ZC sequence is based on a cyclic shift with a cyclic shift value Cmof a multiplication of an original ZC sequence with a shaping sequence.

28. A computer program product comprising a computer-readable storage medium for storing program code which causes a computer or a processor to perform the method (500) of claim 14 or the method (600) of claim 27 when the program code is executed by the computer or the processor.

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