Cqi acquisition method, receiving device and optical communication system for optical communication

Abstract

The application provides a CQI acquisition method, a receiving device and an optical communication system. The method comprises the following steps: receiving a plurality of reference signals transmitted through a channel of optical communication, wherein the transmission power of each reference signal is different; acquiring a channel gain; measuring a plurality of noise powers corresponding to each reference signal according to the received plurality of reference signals; calculating a first noise coefficient related to non-independent noise according to the transmission power of the reference signal, the channel gain and the measured noise power; and acquiring the CQI corresponding to each reference signal by using the corresponding relationship between the first noise coefficient and the CQI stored in advance, and averaging to obtain an average CQI as the CQI of the channel.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a CQI acquisition method, receiving device, and optical communication system for optical communication. Background Technology

[0002] Visible Light Communication (VLC) is a novel wireless optical communication technology that uses light-emitting diodes (LEDs) to transmit information by flashing signals at speeds imperceptible to the human eye. Data before transmission is modulated and encoded, and the light signal carrying the information travels through a channel to the receiver. The photodetector (PD) at the receiver receives the corresponding light signal and provides feedback in the form of electrical current. This electrical signal is amplified and processed, and finally reconstructed into the desired data stream.

[0003] The noise in a VLC system's received signal can generally be categorized into scattering noise and circuit thermal noise. Some studies also classify scattering noise into relative intensity noise and background light noise. Furthermore, due to the physical characteristics of the PD device and the randomness of photon emission from the LED at the transmitting end, the received noise in a real VLC system will include not only components independent of the signal but also components not independent of the signal. Relative intensity noise can be considered as signal-dependent noise related to the current received signal strength, while background light noise and circuit thermal noise are signal-independent noise unrelated to the current received signal. Regarding the impact of signal-independent noise on system performance, existing research indicates that when the ratio of signal-independent noise power to total noise power reaches 50%, the system capacity decreases by 40%; when the ratio reaches 1%, the capacity decreases by 18%.

[0004] In practice, noise measurement and estimation should be approached from two aspects: acquiring the non-independent noise component and the independent noise component. Due to the influence of user location and transmitted signal strength, the non-independent noise of the received signal is dynamically changing. Given the performance degradation caused by non-independent noise, obtaining Channel Quality Information (CQI) becomes a crucial step in reducing the impact of non-independent noise.

[0005] Previously, although radio frequency (RF) communication could be used to obtain the CQI of the wireless optical intensity channel, it did not address the non-independent noise of the signal, which would affect system performance. Summary of the Invention

[0006] The embodiments of the present invention provide a CQI acquisition method, a receiving device, and an optical communication system for optical communication, which are used to solve the problem in the prior art that it is difficult to acquire the CQI of the channel for non-independent noise of the signal.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0008] In a first aspect, embodiments of the present invention provide a method for obtaining CQI in optical communication, comprising: receiving a plurality of reference signals transmitted through an optical communication channel, each reference signal having a different transmission power; obtaining a channel gain; measuring a plurality of noise powers corresponding to each of the received plurality of reference signals; calculating a first noise figure related to non-independent noise based on the transmission power of the reference signals, the channel gain, and the measured noise power; and obtaining the CQI corresponding to each reference signal using a pre-stored correspondence between the first noise figure and CQI, and averaging the results to obtain an average CQI as the CQI of the channel.

[0009] Optionally, the plurality of reference signals include a first reference signal with a transmit power of 0 and a second reference signal with a transmit power of not 0. The step of calculating the first noise figure related to the non-independent noise based on the transmit power of the reference signal, the channel gain, and the measured noise power includes: using the difference between the noise power of the second reference signal and the noise power of the first reference signal, the transmit power of the first reference signal, and the channel gain to calculate the first noise figure corresponding to each second reference signal.

[0010] Optionally, the plurality of reference signals does not include a reference signal with a transmit power of 0. The step of calculating the first noise figure related to non-independent noise based on the transmit power of the reference signal, the channel gain, and the measured noise power includes: calculating the first noise figure using the difference between the noise power of different reference signals, the difference in the transmit power of the different reference signals, and the channel gain.

[0011] Optionally, the multiple reference signals have the same time-domain position but different frequency-domain positions.

[0012] Optionally, the multiple reference signals have the same frequency domain position but different time domain positions.

[0013] Secondly, embodiments of the present invention provide a receiving device for optical communication, comprising: a reference signal receiving module for receiving multiple reference signals transmitted through an optical communication channel, each reference signal having a different transmission power; a channel gain acquisition module for acquiring a channel gain; a noise power measurement module for measuring multiple noise powers corresponding to each of the received multiple reference signals; a first noise figure calculation module for calculating a first noise figure related to non-independent noise based on the transmission power of the reference signals, the channel gain, and the measured noise power; and a CQI acquisition module for acquiring the CQI corresponding to each reference signal using a pre-stored correspondence between the first noise figure and CQI, and averaging the CQI to obtain an average CQI as the CQI of the channel.

[0014] Optionally, the plurality of reference signals include a first reference signal with a transmit power of 0 and a second reference signal with a transmit power of not 0. The first noise figure calculation module uses the difference between the noise power of the second reference signal and the noise power of the first reference signal, the transmit power of the first reference signal, and the channel gain to calculate the first noise figure corresponding to each second reference signal.

[0015] Optionally, the plurality of reference signals does not include a reference signal with a transmit power of 0. The first noise figure calculation module calculates the first noise figure using the difference between the noise power of the different reference signals, the difference between the transmit power of the different reference signals, and the channel gain.

[0016] Optionally, the multiple reference signals have the same time-domain position but different frequency-domain positions.

[0017] Optionally, the multiple reference signals have the same frequency domain position but different time domain positions.

[0018] Thirdly, embodiments of the present invention provide an optical communication system, including: a receiving device as described in the second aspect; and a transmitting device that sends a plurality of reference signals to the receiving device, wherein the receiving device uploads the CQI of the channel to the transmitting device after obtaining the CQI, and the transmitting device adjusts the modulation and coding strategy according to the CQI.

[0019] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0020] The above-described technical solution of the present invention has at least the following beneficial effects:

[0021] Based on the characteristics of noise in optical communication, this invention can measure the independent and non-independent noise components in visible light noise. It can obtain the channel's CQI for the non-independent noise component and provide assistance for subsequent MCS (Modulation and Coding Scheme) adjustments based on the CQI measurement results to reduce performance loss. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0023] Figure 1 This is a flowchart of a CQI acquisition method according to an embodiment of the present invention.

[0024] Figure 2 This is a flowchart of a CQI acquisition method according to another embodiment of the present invention.

[0025] Figure 3 This is a structural diagram of an optical communication receiving device according to an embodiment of the present invention.

[0026] Figure 4 This is a flowchart illustrating the processing of the receiving device according to an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the time-frequency configuration of the reference signal according to an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram of another time-frequency configuration of the reference signal according to an embodiment of the present invention.

[0029] Figure 7 This is a structural diagram representing the existing VLC-SISO transceiver system. Detailed Implementation

[0030] Figure 7 This is a structural diagram representing the existing VLC-SISO (Single-Input Single-Output) transceiver system.

[0031] In a VLC communication system, the transmitting circuit sends an electrical signal to the transmitter (transmitting device) via DC bias. The transmitter is typically composed of LEDs, which have high sensitivity. Additionally, to accommodate illumination, white LEDs or red-green-blue LEDs can be used as the transmitter. A photodetector receives the optical signal and converts it into an electrical signal, which is then sent to the receiving circuit. The received optical power equals the optical power after channel fading plus the independent noise power and the non-independent noise power caused by the received optical power. This invention addresses the Channel Quality Indication (CQI) for acquiring channels with non-independent noise.

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] The term "power" as used in this invention can be either "optical power" or "electrical power," but unless otherwise specified, it is assumed to be "optical power." Furthermore, "first noise" refers to non-independent noise, and "second noise" refers to independent noise.

[0034] The following provides a detailed description of the CQI acquisition method for optical communication according to embodiments of this application.

[0035] Figure 1 This is a flowchart of a CQI acquisition method according to an embodiment of the present invention. This method can be applied to VLC systems, which typically have a transmitter (hereinafter sometimes referred to as TX) and a receiver (hereinafter sometimes referred to as RX).

[0036] In step S101, reference signals are transmitted from the TX to the RX of the VLC system in groups for noise measurement. Each group of reference signals corresponds to one RX, and each group includes at least two reference signals. The reference signal settings need to meet the following two conditions simultaneously: (1) the reference signals in the group are transmitted at different powers; (2) the different reference signals in the group occupy different time-frequency resources.

[0037] The VLC system's transmitter transmits a reference signal RS0 with a power of 0, a reference signal RS1 with a power of P1, and so on, with a power of P... N The reference signal RSN (if expressed in terms of electrical power, then the electrical power of the reference signal RSi is f(P)) i (where f represents the conversion from optical power to electrical power).

[0038] Figure 5 This is a schematic diagram of the time-frequency configuration of the reference signal according to an embodiment of the present invention.

[0039] exist Figure 5 In the diagram, the horizontal axis represents time, and the vertical axis represents frequency. This figure illustrates a method that uses the same reference signal transmitted in the time domain but different reference signals transmitted in the frequency domain.

[0040] Figure 6 This is a schematic diagram of another time-frequency configuration of the reference signal according to an embodiment of the present invention.

[0041] exist Figure 6 In this study, the same reference signal was transmitted in the frequency domain, while different reference signals were transmitted in the time domain.

[0042] Either of the two time-frequency configurations can be used.

[0043] In step S102, the channel gain h is obtained at the receiving end. The method for obtaining the channel gain can be, for example, existing techniques such as evaluating and quantizing the CSI at the receiving end.

[0044] In step S103, the noise power is measured at the receiving end based on each transmitted reference signal. The received noise power N0 is obtained from RS0, the received noise power N1 from RS1, the received noise power N2 from RS2, and so on, until the received noise power N2 is obtained from RSN. N .

[0045] Next, the difference between the noise power of the reference signal with non-zero power and the noise power of the reference signal with zero power (RS0) is calculated as the corresponding first noise power. For example, the first noise power corresponding to the signal RS1 is N1-N0, the first noise power corresponding to the signal RS2 is N2-N0, and so on, the first noise power corresponding to the signal RSN is N... N -N0.

[0046] In step S104, at the receiving end, based on the channel gain h, the transmit powers P1, P2…P of each reference signal are calculated. N Based on the first noise power corresponding to each reference signal obtained above, the first noise figure is calculated. For example, the first noise figure obtained from the RS1 signal is:

[0047]

[0048] The first noise figure calculated from the RS2 signal is:

[0049]

[0050] In step S105, since the first noise figure for each signal is calculated at the receiving end, the CQI of each reference signal is obtained based on this figure. A table showing the correspondence between the first noise figure and the CQI can be stored in advance in memory. The CQI is obtained by indexing this table. Then, the CQIs of the N reference signals are averaged to obtain the average CQI as the channel's CQI, and this average is reported to TX.

[0051] In step S106, TX adjusts the modulation and coding strategy (MCS) based on the obtained average CQI.

[0052] According to this embodiment, by using a reference signal with zero power, the first noise power generated by each reference signal is obtained. Based on the characteristics of visible light noise, the independent noise part and the non-independent noise part in the visible light noise can be measured, so as to obtain the CQI more appropriately and provide assistance for subsequent MCS adjustment.

[0053] In the above embodiment, the transmitted reference signal includes a reference signal RS0 with zero power, thereby enabling the acquisition of the first noise power corresponding to different signals. However, a reference signal without zero power can also be used to obtain the CQI.

[0054] Figure 2 This is a flowchart of a CQI acquisition method according to another embodiment of the present invention.

[0055] In step S101a, the VLC system's transmitter transmits a reference signal RS1... with power P1. N The reference signal RSN, and similarly, the number of reference signals is at least two.

[0056] The processing in step S102 remains unchanged, and the channel gain is obtained.

[0057] In step S103, the noise power N1…N generated by each reference signal is measured in the same manner. N .

[0058] In step S104a, at the receiving end, the difference between different noise powers is calculated based on a certain noise power. Here, the lowest noise power N1 is selected as the benchmark, and the differences N2-N1, N3-N1…N are calculated. N -N1. Based on the channel gain h, the transmit power P1, P2…P of each reference signal. N The first noise figure is calculated based on the noise power difference. For example, the first noise figure obtained from the RS2 signal is:

[0059]

[0060] The first noise figure calculated from the RS3 signal is:

[0061]

[0062] The processing for S105 and S106 is the same: obtain the average CQI and report it to TX.

[0063] This variation allows for the appropriate acquisition of CQI even without transmitting a reference signal with zero power, thus facilitating the adjustment to an MCS that reduces performance loss.

[0064] like Figure 3 As shown, embodiments of the present invention also provide a receiving device for optical communication. Figure 4 This is a flowchart of the processing of the receiving device.

[0065] The receiving device 1 of the present invention includes a reference signal receiving module 10, a noise power measurement module 20, a channel gain acquisition module 30, a first noise figure calculation module 40, and a CQI acquisition module 50.

[0066] Reference signal receiving module 10 receives reference signal RS0 with power of 0, reference signal RS1 with power of P1, and so on, with power of P... N The reference signal RSN (step S201).

[0067] The channel gain acquisition module 30 acquires the channel gain (step S202).

[0068] The noise power measurement module 20 measures the noise power at the receiving end, obtaining the received noise power N0 based on RS0, N1 based on RS1, N2 based on RS2, and so on, until obtaining the received noise power N1 based on RSN. N (Step S203).

[0069] The first noise figure calculation module 40 calculates the first noise power corresponding to different reference signals. For example, the first noise power corresponding to the RS1 signal is N1-N0. Based on the channel gain h, the transmit power P1, P2…P… of each reference signal… N The first noise figure is calculated by taking the first noise power corresponding to each reference signal and calculating it using the formula in the CQI acquisition method described above (step S204).

[0070] The CQI acquisition module 50 acquires the CQI based on the first noise parameter according to the pre-stored correspondence table, and performs averaging (step S205).

[0071] This embodiment also achieves the following effect: it can measure the independent noise component and the non-independent noise component in visible light noise, obtain the CQI more appropriately, and provide assistance for subsequent MCS adjustment.

[0072] Furthermore, since the receiving device in the above embodiment uses a method that includes a reference signal with zero power, it is also possible to use a method that does not include a reference signal with zero power.

[0073] The above embodiments are illustrated using a visible light communication system as an example. However, in addition to visible light scenarios, the CQI acquisition method and apparatus described above can be applied to all scenarios with the same channel characteristics, including but not limited to non-visible light communication, infrared communication, ultraviolet communication, and terahertz communication. They can also achieve the same effect as the visible light communication system, with the same processing flow, and therefore will not be elaborated upon here.

[0074] It should be noted that in the above embodiments, CQI is acquired at the receiving end, but the first noise figure can also be sent to the transmitting end, and CQI is acquired at the transmitting end.

[0075] This application embodiment also provides a readable storage medium storing a program or instructions that, when executed by a processor, implement the above-described functionality. Figure 1 or Figure 2 The various processes of the method embodiments shown can achieve the same technical effect, and will not be described again here to avoid repetition.

[0076] The processor mentioned above is the processor in the terminal described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0077] The steps of the methods or algorithms described in this application can be implemented in hardware or by executing software instructions on a processor. The software instructions can consist of corresponding software modules, which can be stored in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, portable hard disk, read-only optical disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can be housed in an ASIC. Alternatively, the ASIC can be housed in a core network interface device. Of course, the processor and storage medium can also exist as discrete components in the core network interface device.

[0078] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this application can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0079] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

[0080] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, embodiments of this application can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of this application can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] This application describes embodiments of methods, apparatus (systems), and computer program products according to embodiments of this application with reference to flowchart illustrations and / or block diagrams. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0082] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0083] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0084] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A method for obtaining CQI in optical communication, characterized in that, include: It receives multiple reference signals transmitted via an optical communication channel, each with a different transmission power; Obtain channel gain; Based on the received multiple reference signals, multiple noise powers corresponding to each reference signal are measured; The first noise figure related to the non-independent noise is calculated based on the transmit power of the reference signal, the channel gain, and the measured noise power. as well as Using the pre-stored correspondence between the first noise figure and CQI, the CQI corresponding to each reference signal is obtained, and the average CQI is obtained by averaging the values ​​to obtain the average CQI as the CQI of the channel; the average CQI is used to adjust the modulation and coding strategy. The plurality of reference signals includes a first reference signal with a transmit power of 0 and a second reference signal with a transmit power of not 0. The step of calculating the first noise figure related to the non-independent noise based on the transmit power of the reference signal, the channel gain, and the measured noise power includes: The first noise figure corresponding to each second reference signal is calculated using the difference between the noise power of the second reference signal and the noise power of the first reference signal, the transmit power of the first reference signal, and the channel gain.

2. The CQI acquisition method according to claim 1, characterized in that, The plurality of reference signals does not include the reference signal with a transmit power of 0. The step of calculating the first noise figure related to the non-independent noise based on the transmit power of the reference signal, the channel gain, and the measured noise power includes: The first noise figure is calculated using the difference between the noise power of different reference signals, the difference in the transmit power of the different reference signals, and the channel gain.

3. The CQI acquisition method according to any one of claims 1 to 2, characterized in that, The multiple reference signals have the same time-domain position but different frequency-domain positions.

4. The CQI acquisition method according to any one of claims 1 to 2, characterized in that, The multiple reference signals have the same frequency domain position but different time domain positions.

5. A receiving device for optical communication, characterized in that, include: The reference signal receiving module is used to receive multiple reference signals transmitted through the optical communication channel, each reference signal having a different transmission power; Channel gain acquisition module, used to acquire channel gain; A noise power measurement module is used to measure multiple noise powers corresponding to each of the received multiple reference signals; The first noise figure calculation module is used to calculate the first noise figure related to the non-independent noise based on the transmission power of the reference signal, the channel gain, and the measured noise power. as well as The CQI acquisition module is used to acquire the CQI corresponding to each reference signal by utilizing the pre-stored correspondence between the first noise figure and CQI, and to average the CQI to obtain the average CQI as the CQI of the channel; the average CQI is used to adjust the modulation and coding strategy. The plurality of reference signals includes a first reference signal with a transmit power of 0 and a second reference signal with a transmit power of not 0. The first noise figure calculation module uses the difference between the noise power of the second reference signal and the noise power of the first reference signal, the transmit power of the first reference signal, and the channel gain to calculate the first noise figure corresponding to each second reference signal.

6. The receiving device according to claim 5, characterized in that, The plurality of reference signals does not include the reference signal with a transmit power of 0. The first noise figure calculation module calculates the first noise figure using the difference between the noise power of different reference signals, the difference in the transmit power of the different reference signals, and the channel gain.

7. The receiving device according to any one of claims 5 to 6, characterized in that, The multiple reference signals have the same time-domain position but different frequency-domain positions.

8. The receiving device according to any one of claims 5 to 6, characterized in that, The multiple reference signals have the same frequency domain position but different time domain positions.

9. An optical communication system, characterized in that, include: The receiving device as described in any one of claims 5 to 8; as well as The transmitting device sends multiple reference signals to the receiving device. After obtaining the CQI of the channel, the receiving device uploads it to the transmitting device, and the transmitting device adjusts the modulation and coding strategy according to the CQI.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 4.

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