Channel equalization method and device for multi-user communication system
A multi-user communication, multi-user technology, applied in the field of channel equalization, which can solve problems such as far from optimal receivers
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no. 1 example
[0068] In the first embodiment of the present invention, both temporal pre-equalization and spatial pre-equalization can be performed in a single stage (7, 8), as shown in FIG. 3 . For the frequency index , the frequency-domain samples received from all antennas (1A, 1B) are represented by
[0069] , which is based on the time interval (or block) of received samples. This block passes to enumerate. Frequency-domain spatial and temporal pre-equalization (8) as with The element-wise multiplication of . we got
[0070]
[0071] in
[0072]
[0073] and among them is the frequency-domain representation of a scalar spectral shaping filter (SSF), such as a raised cosine filter. it's here, is the result of the Cholesky factorization of the multi-antenna periodogram, namely
[0074]
no. 2 example
[0076] In the second embodiment of the present invention, MMSE pre-equalization can be divided into two stages: first temporal pre-equalization (9, 11), and then spatial decorrelation (10, 12). See Figures 4a and 4b for two alternative embodiments of this spatial and temporal pre-equalization.
[0077] In the first stage, for the number of antennas α, temporal pre-equalization (11) employs frequency-domain filter coefficients
[0078]
[0079] carry out, where is a scalar spectral shaping filter (SSF), such as a raised cosine filter, and is the frequency and block number A single-antenna periodogram. Notice, is real-valued and positive, which simplifies square root and division calculations.
[0080] For the number of antennas α, the periodogram can be estimated as a moving average
[0081]
[0082] in, is the appropriate scaling factor, e.g. . Alternatively, estimate the periodogram recursively,
[0083]
[0084] in, is an appropriate forgetting f...
no. 3 example
[0102] In a third embodiment of the invention, the frequency-domain spatial decorrelation as described in the second stage of the previous subsection is performed in the time domain (10). For an illustration of this spatial and temporal pre-equalization, see Figure 5 .
[0103] At the first level, temporal pre-equalization (11) is done as in the previous node, i.e. as an element-wise scalar multiplication
[0104]
[0105] For each antenna α, frequency index and block ,in
[0106]
[0107] The time-domain form of the time-pre-equalized signal of antenna α is expressed as
[0108]
[0109] By using an "overlap and add" approach such as Figure 7 As shown, a new time domain sequence is constructed. This is determined by each antenna α is represented by and the runtime index is continuous sequence of . In vector representation, time The temporally pre-equalized signal is expressed as
[0110]
[0111] In the second stage, time domain spatial decorrelati...
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