Method for jointly estimating and compensating residual common phase noise by multiple reference signals

Abstract

The invention discloses a method for jointly estimating and compensating residual common phase noise through multiple reference signals, and relates to the field of wireless communication. The method comprises the following steps: firstly, calculating LS estimation at a reference signal symbol position, then calculating residual common phase noise at the reference signal symbol position by using an LS estimation value and a channel estimation value output by a superior module, and then calculating residual common phase noise at a data symbol position according to the residual common phase noise at the reference signal symbol position. And finally compensating residual common phase noise at all symbol positions. According to the method, multiple reference signals are used for joint estimation, the estimation precision of the residual common phase noise can be improved, the performance degradation of the system caused by the residual common phase noise is further reduced, the complexity is low, and the method is easy to implement.

Description

Technical Field

[0001] The invention relates to the field of wireless communications, and in particular to a method for jointly estimating and compensating residual common phase noise using multiple reference signals. Background Art

[0002] With the development of Internet technology, mobile data traffic has exploded, and the fifth generation mobile communication system (5G) has come into being. 5G has made major breakthroughs in data transmission rate, system bandwidth and supported carrier frequency. In terms of carrier frequency, 5G supports higher frequency bands, and a core problem brought about by high-frequency band communications is that communication devices are subject to process limitations, resulting in some uncontrollable non-ideal characteristics, including nonlinear distortion of power amplifiers, residual common phase noise introduced by oscillators, and IQ imbalance. The 3GPP working group clearly stipulates that when the carrier frequency is higher than 6GHz, the estimation and compensation of residual common phase noise must be considered to reduce the negative impact of residual common phase noise on system performance. However, in existing methods, only one reference signal, PTRS, is usually used to estimate the residual common phase noise, and the estimation accuracy is not high. Summary of the invention

[0003] In view of this, the present invention proposes a method for jointly estimating and compensating residual common phase noise using multiple reference signals. The method uses multiple reference signals for joint estimation, which can improve the estimation accuracy of residual common phase noise, thereby further reducing the performance degradation caused by residual common phase noise to the system, and has low complexity and is easy to implement.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A method for jointly estimating and compensating residual common phase noise using multiple reference signals is used to estimate residual common phase noise in 5G signals and perform channel estimation compensation; the method comprises the following steps:

[0006] Step 1: At all reference signal positions, use the received reference signal refSymRx and the local reference signal refSymLocal to perform LS estimation and obtain the corresponding LS estimation value H_ls(k,l):

[0007] H_ls(k,l)=conj(refSymLocal(k,l))·refSymRx(k,l);

[0008] Where k is the subcarrier index, l is the symbol index, and conj(·) means conjugation.

[0009] Step 2: At all reference signal positions, the residual common phase noise rough estimate cpe_temp(l) is calculated using the LS estimate H_ls(k, l) and the channel estimate Hd(k, l) output by the upper module:

[0010]

[0011] Step 3: At all reference signal positions, calculate the precise residual common phase noise cpe(l) based on the rough estimate of the residual common phase noise cpe_temp(l):

[0012]

[0013] Step 4, for a pure data symbol, if the pure data symbol is the last symbol among all symbols, the residual common phase noise of the pure data symbol is equal to the residual common phase noise of the second to last symbol among all symbols, otherwise the residual common phase noise cpe(l) of the pure data symbol is calculated using linear interpolation:

[0014]

[0015] Step 5, compensating the channel estimation value Hd(k, l) according to the residual common phase noise of each symbol:

[0016] cpeHd(k,l)=Hd(k,l)·cpe(l);

[0017] Among them, cpeHd(k, l) is the compensated channel estimation output value.

[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention compared with the prior art are:

[0019] The present invention uses multiple reference signals for joint estimation, which can improve the estimation accuracy of the residual common phase noise, thereby further reducing the performance degradation of the system caused by the residual common phase noise, and has low complexity and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an overall flow chart of a method for jointly estimating and compensating residual common phase noise using multiple reference signals in an embodiment of the present invention.

[0021] Figure 2 4 is a data constellation diagram of the residual common phase noise not compensated in an embodiment of the present invention.

[0022] Figure 3 This is a data constellation diagram for compensating residual common phase noise in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] A method for jointly estimating and compensating residual common phase noise using multiple reference signals is used to estimate the residual common phase noise in 5G signals and perform channel estimation compensation; Figure 1 As shown, the following steps are included;

[0025] At all DMRS and PTRS symbol positions, LS estimation is performed using the received reference signal refSymRx and the local reference signal refSymLocal:

[0026] H_ls(k,l)=conj(refSymLocal(k,l))·refSymRx(k,l);

[0027] Specifically, in this embodiment, the starting symbol position of PDSCH in the time domain is 0, the symbol length is 13, and the number of RBs occupied in the frequency domain is 272. PDSCH has two reference signals, including DMRS and PTRS. The symbol positions of DMRS in the time domain are 2, 7, and 11, and the density in the frequency domain is 2RE; the symbol positions of PTRS in the time domain are 0, 4, 6, and 9, and the density in the frequency domain is 2RB, and the RE offset within the RB is 0.

[0028] The subcarrier index k of the reference signal is 0, 24, 48, ..., 3240; the symbol index l of the DMRS is 2, 7, 11, and the symbol index l of the PTRS is 0, 4, 6, 9.

[0029] At all DMRS and PTRS symbol positions, the conjugate value of the LS estimation value H_ls is multiplied by the channel estimation value Hd of the upper module to obtain the residual common phase noise cpe_temp, and the residual phase noise on each symbol is accumulated and normalized to obtain the accurate residual common phase noise value cpe on each symbol:

[0030]

[0031]

[0032] The pure data symbol index l of PDSCH is 1, 3, 5, 8, 10, 12. For the PDSCH symbols with symbol index l of 1, 3, 5, 8, 10, the residual common phase noise values ​​on these symbols are calculated using linear interpolation:

[0033]

[0034] The residual common phase noise value for the PDSCH symbol with symbol index l being 12 is equal to the residual common phase noise value of the previous symbol:

[0035] cpe(12)=cpe(11);

[0036] For each PDSCH symbol, the channel estimation output value is compensated by the residual common phase noise value on the symbol.

[0037] cpeHd(k,l)=Hd(k,l)·cpe(l);

[0038] k=0, 1, 2,...,3263, l=0,1,2,...,12.

[0039] Specifically, Figure 2 , Figure 3 As shown, after compensating for the residual common phase noise, the rotation of the data on the constellation diagram is alleviated.

[0040] In summary, the present invention uses multiple reference signals for joint estimation, which can improve the estimation accuracy of the residual common phase noise, thereby further reducing the performance degradation of the system caused by the residual common phase noise, and has low complexity and is easy to implement.

[0041] Those skilled in the art will appreciate that the embodiments described are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to the embodiments described. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for jointly estimating and compensating residual common phase noise using multiple reference signals, which is used to estimate the residual common phase noise in 5G signals and perform channel estimation compensation; characterized in that: The steps include: Step 1: At all reference signal positions, use the received reference signal refSymRx and the local reference signal refSymLocal to perform LS estimation and obtain the corresponding LS estimation value H_ls(k,l): H_ls(k,l)=conj(RefSymLocal(k,l))·refSymRx(k,l); Where k is the subcarrier index, l is the symbol index, and conj(·) means conjugation. Step 2: At all reference signal positions, the residual common phase noise rough estimate cpe_temp(l) is calculated using the LS estimate H_ls(k,l) and the channel estimate Hd(k,l) output by the upper module: Step 3: At all reference signal positions, calculate the precise residual common phase noise cpe(l) based on the rough estimate of the residual common phase noise cpe_temp(l): Step 4: For a pure data symbol, if the pure data symbol is the last symbol among all symbols, the residual common phase noise of the pure data symbol is equal to the residual common phase noise of the second to last symbol among all symbols; otherwise, the residual common phase noise of the pure data symbol is calculated using linear interpolation. cpe(l): Step 5, compensate the channel estimation value Hd(k,l) according to the residual common phase noise of each symbol: cpeHd(k,l)=Hd(k,l)·cpe(l); Among them, cpeHd(k,l) is the compensated channel estimation output value.

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