Method for lowering BPSK (binary phase shift keying) constellation mapping signal bit error rate under fading channel
A constellation mapping and fading channel technology, applied in the field of modulation and demodulation, can solve the problems of long time, increase the wireless access process and time, and complex demodulation process, and achieve convenient implementation, reduce transmission delay, modulation and demodulation. The effect of tuning the process is simple
Inactive Publication Date: 2015-03-11
SOUTH CHINA UNIV OF TECH
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However, this method needs to predict the channel status at the transmitter, which undoubtedly increases the wireless access process and time. In the mobile communication system, some signals need to be demodulated quickly, such as the downlink physical control channel. It is possible to predict the channel status of each receiver; the patent application number 98122601.9 proposes a multi-element modulation and demodulation technology using orthogonal codes, and divides the transmitted signal into LN bit-long blocks at the sending side, and each block is divided into Divide into N groups of L-bit data sequences, and then encode the data sequences. After receiving the signal, the receiving side calculates the correlation value between the laser signal and each possible orthogonal code, and determines the corresponding orthogonal code and its value according to the maximum correlation value. data sequence, but the demodulation process of this method is complicated and takes a long time
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[0021] Such as figure 1 As shown, a method for reducing the bit error rate of BPSK constellation mapping signals in a fading channel includes the following steps:
[0022] Suppose the data bit stream to be transmitted is T=[1,1,0,1,1,0,0,1,1], and the BPSK constellation mapping method is [1,1,-1,1,1,-1 ,-1,1,1];
[0023] (1) Assuming that the segment length of the data bit stream is determined to be 9 according to the delay that the communication system can bear, then the above data bit stream can just be divided into one section;
[0024] (2) The random mapping function generated is f(1)=2, f(2)=5, f(3)=1, f(4)=3, f(5)=7, f(6)=4 , f(7)=8, f(8)=9, f(9)=6, its inverse function is:
[0025] f -1 (1)=3, f -1 (2)=1,f -1 (3)=4, f -1 (4)=6, f -1 (5)=2, f -1 (6)=9, f -1 (7)=5, f -1 (8)=7, f -1 (9)=8, then [1,2,3,4,5,6,7,8,9] is mapped to [2,5,1,3,7,4,8,9,6] through a random function , that is, [1,2,3,4,5,6,7,8,9] corresponds to [3,1,4,6,2,9,5,7,8].
[0026] (3) The QPSK...
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The invention discloses a method for lowering BPSK (binary phase shift keying) constellation mapping signal bit error rate under a fading channel. The method is characterized by including the following steps: 1, determining segment length N of data bit flow according to time delay bearable for a communication system, wherein a relation between generated time delay tou and the segment length N meets a formula: tou=2.N.T, tou refers to generated time delay, and T refers to sampling period; segmenting binary bit flow to be transmitted according to the segment length N; 2, generating a random mapping function f, wherein f (i)<[1,N], and if i= / j, f(i)= / f(j); determining an inverse function f-1(k); 3, performing QPSK (quadrature phase shift keying) mapping on the data bit flow after being segmented; 4, demodulating after a receiving end receives an emitting signal. The method has the advantages that diversity receiving of the receiving end is realized, nit error rate in demodulating of the receiving end under the fading channel is lowered, complexity and cost in realization are lowered, and the like.
Description
technical field [0001] The invention relates to a mobile communication technology, in particular to a method for reducing the bit error rate of BPSK constellation mapping signals in a fading channel, which is a modulation and demodulation method capable of reducing the bit error rate of BPSK constellation mapping signals in a fading channel . Background technique [0002] Time-frequency fading is a common problem faced by mobile communications. Due to the influence of multipath effect and Doppler frequency shift, the signal will experience time and frequency fading after passing through the wireless channel, and there will be large fluctuations in both the time domain and the frequency domain. , leading to an increase in the bit error rate of demodulation. In order to solve this problem, many patents have proposed solutions. For example, the patent application number 200810115890.5 proposes a method and device for demapping constellation mapping. +β·D) Constellation diagra...
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IPC IPC(8): H04L27/18
CPCH04L27/18
Inventor 杨俊
Owner SOUTH CHINA UNIV OF TECH