Recoverable multi-linear companding method lowering peak-to-average ratio of ACO-OFDM system
A peak-to-average ratio and linear technology, applied in the field of visible light communication, can solve problems such as nonlinear distortion, reduction, and amplitude ambiguity
Active Publication Date: 2016-08-17
上海瀚芯实业发展合伙企业(有限合伙)
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[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a recoverable multi-segment linear companding method that reduces the peak-to-average ratio in the ACO-OFDM system, so as to overcome the ambiguous amplitude and non-linear companding methods that exist in traditional companding transforms. linear distortion etc.
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[0030] The present invention will be further described below in conjunction with the accompanying drawings.
[0031] The embodiment of the present invention discloses a recoverable multi-segment linear companding scheme that reduces the peak-to-average ratio in the ACO-OFDM visible light communication system, such as figure 1 As shown, the communication channel is assumed to be an additive white Gaussian noise channel. The method of the embodiment of the present invention mainly includes the following steps:
[0032] (1) The transmitter sends the ACO-OFDM signal after recoverable multi-segment linear companding transformation
[0033] Step 1: After the input signal undergoes serial-to-parallel conversion and constellation mapping, subcarrier allocation is performed on it to obtain a discrete sequence X in the frequency domain, and IFFT operation is performed on X to obtain a discrete sequence x in the time domain, and the negative value in x is clipped to Zero to get the fin...
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The present invention discloses a recoverable multi-linear companding method lowering a peak-to-average ratio of an ACO-OFDM system. A recoverable multi-linear companding unit is introduced in a transmit end, a corresponding de-companding module is introduced in a receive end, and a maximum posterior probability (MAP) rule is used for data recovery in the receive end. The method includes a first step that the transmit end performs recoverable multi-linear companding on an ACO-OFDM signal and then sends the signal; and a second step that the receive end uses the maximum posterior probability rule to detect a received signal and performs corresponding de-companding, so as to recover the sent data. According to the method, due to use of a special structure of an ACO-OFDM time domain signal, a problem that signal amplitudes before and after segmented linear change are not in one-to-one correspondence is solved, multi-linear companding is possible, a good PAPR suppression result is achieved with low complexity, and BER performance of a system is ensured.
Description
technical field [0001] The invention relates to a recoverable multi-segment linear companding method for reducing the peak-to-average ratio in an ACO-OFDM system, which belongs to the visible light communication technology. Background technique [0002] As an efficient modulation technology, OFDM's high spectrum utilization makes it possible to realize high-speed visible light communication under the condition of limited modulation bandwidth. Complexity, optimize system performance, so it has been widely used in visible light communication in recent years. Some OFDM schemes suitable for visible light communication systems have been gradually proposed, among which there are three main ones, namely DC-biased optical OFDM (DCO-OFDM), asymmetrically limited optical OFDM ( ACO-OFDM) and Pulse Amplitude Modulation Orthogonal Frequency Division Multiplexing (PAM-OFDM). [0003] The rate gain brought by OFDM modulation is very obvious, but it also brings new problems. There is a ...
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Login to View More IPC IPC(8): H04L27/26
CPCH04L27/2615
Inventor 陈明管瑞唐洋
Owner 上海瀚芯实业发展合伙企业(有限合伙)