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Space-time continuous phase modulation (CPM) signal modulation and demodulation methods

A modulation method and signal technology, applied in the field of communication, can solve problems such as high computational complexity and increased computational complexity

Inactive Publication Date: 2011-09-28
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The computational complexity of this method is high
In a multi-antenna (MIMO, multiple-input-multiple-output) CPM signal system, if the receiving end still uses ML detection, the computational complexity will further increase

Method used

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  • Space-time continuous phase modulation (CPM) signal modulation and demodulation methods
  • Space-time continuous phase modulation (CPM) signal modulation and demodulation methods
  • Space-time continuous phase modulation (CPM) signal modulation and demodulation methods

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0069] Here, take the CPM modulation with memory length L=1 as an example:

[0070] (1) After constellation mapping, the two segments of source bits at the sending end are: x 1 =[x 1(1), x 1 (2) L x 1 (2N)], x 2 =[x 2 (1),x 2 (2) L x 2 (2N)], in order to ensure that the signal phase of the original data and time-reversed and processed data is still continuous after adding CP, two redundant symbols are added to the original data, x′ 1 =[x 1 (1),1,x 1 (2) L x 1 (2N), 1], x' 2 =[x 2 (1), -1, x 2 (2) L x 2 (2N), 1];

[0071] let x' 1 (0)=x' 2 (0)=1, the first precoding is performed in the following way:

[0072] alpha 1 (n)=(-1) n-1 x' 1 (n-1)x' 1 (n)

[0073] alpha 2 (n)=(-1) n-1 x' 2 (n-1)x' 2 (n)

[0074] Get the data after the first precoding: α 1 =[α 1 (1), α 1 (2) L α 1 (2N+2)]; α 2 =[α 2 (1), α 2 (2) L α 2 (2N+2)].

[0075] (2) For the data α after the first precoding 1 , α 2 sum separately. like Then the data block can ensure that t...

Embodiment 2

[0105] An example where L is greater than 1: (1) The two segments of source bits at the sending end are mapped to the constellation: x 1 =[x 1 (1),x 1 (2) L x 1 (2N)], x 2 =[x 2 (1),x 2 (2) L x 2 (2N)], add two sections of redundant symbols f=[f(1), L, f(L)] and e=[e(1), L, e(L)] for the original data, obtain:

[0106] x' 1 =[x 1 (1), f 1 (1), L, f 1 (L),x 1 (2) L x 1 (2N), e 1 (1), L, e 1 (L)]

[0107] x' 2 =[x 2 (1), f 2 (1), L, f 2 (L), x 2 (2) L x 2 (2N), e 2 (1), L, e 2 (L)]

[0108] where f 2 (1)=-e 2 (L), f 2 (1)=-e 2 (L).

[0109] (2) Let x' 1 (0)=x' 2 (0)=1, precoding is performed as follows:

[0110] alpha 1 (n)=(-1) n-1 x' 1 (n-1)x' 1 (n)

[0111] alpha 2 (n)=(-1) n-1 x' 2 (n-1)x' 2 (n)

[0112] Get the precoded data: α 1 =[α 1 (1), α 1 (2) L α 1 (2N+2L)]; α 2 =[α 2 (1), α 2 (2) L α 2 (2N+2L)] for the precoded data α 1 , α 2 sum separately. like Then the data block can ensure that the phase is still continuous afte...

Embodiment 3

[0143] The transmitting part of the present invention uses precoding and time inversion processing, so that the receiving end can realize signal detection through simple linear processing after Laurent matched filtering, figure 2 Work flow chart for the receiver:

[0144] Including: down-conversion, remove CP and header symbols, matched filtering, FFT, space-time solution, and frequency-domain equalization, IFFT, decision, inverse mapping:

[0145] The receiving part mainly transforms the signal into the frequency domain through FFT to form the Alamouti space-time scheme in the frequency domain to obtain diversity and achieve equalization in the frequency domain for multipath channels.

[0146] The signal at the receiving end passes through the down-conversion part and becomes a baseband signal.

[0147] For L=1, the CPM signal of modulation factor h=1 / 2 can be expressed as follows:

[0148] s ( t ) = ...

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Abstract

The invention discloses a space-time continuous phase modulation (CPM) signal modulation method and a space-time CPM signal demodulation method. By the space-time CPM signal modulation method for preprocessing a CPM signal before modulation, a receiver can demodulate the received CPM signal in a linear signal demodulation way to reduce the demodulation complexity. Before CPM modulation is performed on a transmission sequence, the preprocessing before the modulation is performed at first, and comprises a segmented mapping step, an intra-segment redundancy addition step, a primary precoding step, an intra-segment redundancy regulation step, a time reversal and negation step, a secondary precoding step, a cyclic prefix addition step, an intra-segment redundancy addition step and a space-time signal formation step. In the methods, a transmitter adds cyclic prefixes to the sequence, and a signal received by the receiver is the cyclic convolution of a transmitted signal and a channel; therefore, when receiving the modulated CPM signal, the receiver can demodulate the CPM signal in the linear signal demodulation way.

Description

technical field [0001] The invention belongs to the technical field of communication, in particular to a continuous phase modulation system using multiple antennas (MIMO). Background technique [0002] Continuous phase modulation (continuous phase modulation, CPM) has high power and bandwidth efficiency, and has received extensive attention in power and bandwidth limited systems. Its constant envelope characteristic enables it to be amplified by an inexpensive nonlinear amplifier, and there is no high PAPR problem of linear modulation in high-order modulation. These excellent characteristics make the CPM signal have broad application prospects in digital communication, and become one of the main candidate technologies for future mobile multimedia communication. [0003] The power normalized CPM signal s(t) can be expressed as: [0004] [0005] [0006] Represents the time-varying phase carrying information, where h=h m / h n is the modulation index (modulation fa...

Claims

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Application Information

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IPC IPC(8): H04L27/20H04B7/06H04L1/00H04L25/03
Inventor 罗胜李强严庆胡玓秀
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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