Adaptive modulation method for optimizing peak-to-average power ratio (PAPR)

A technology of peak-to-average power and adaptive modulation, which is applied in the field of communication and can solve problems such as high peak-to-average power ratio

Inactive Publication Date: 2012-01-18
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the Greedy algorithm based on OFDM produces a very high peak-to-average power ratio, and proposes an adaptive modulation method for optimizing the peak-to-average power ratio

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  • Adaptive modulation method for optimizing peak-to-average power ratio (PAPR)

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Embodiment Construction

[0055] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0056] CI-OFDM is a new mechanism proposed in recent years. While retaining OFDM's high spectrum utilization and the ability to resist frequency selective fading, CI-OFDM extends each channel of low-speed parallel data to all sub-channels with orthogonal CI codes. Simultaneous transmission on the carrier, thus resulting in frequency domain diversity gain, compared with the traditional OFDM system has better BER performance. In the CI-OFDM system, the CI code can evenly stagger the peak value of the time-domain waveform of each data modulation, instead of adding many random sinusoidal signals like OFDM, thus eliminating the problem of excessive peak-to-average power ratio.

[0057] The present invention aims at optimizing the peak-to-average power ratio when the service quality and transmission rate are constant, and aims at the problem of high ...

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Abstract

The invention discloses an adaptive modulation method for optimizing a peak-to-average power ratio (PAPR). The method provided by the invention is improved on the basis of a traditional Greedy adaptive bit allocation method, and m bits are allocated to a subcarrier every time, thus, the complexity in computing is reduced; meanwhile, the modulation ways of the m number of bits can also be flexibly matched; next, CI-OFDM (Carrier Interferometry-Orthogonal Frequency Division Multiplexing) is regarded as a power linear amplitude limiting way, N subcarriers are divided into subcarriers subjected to CI expansion and subcarriers not subjected to CI expansion through a single-threshold step or a double-threshold step, the PAPR is limited by a power threshold, and respective advantages of OFDM and the CI-OFDM are combined, so that the optimization of transmitting power and the PAPR is realized under the condition that the service quality and the transmission rate are fixed.

Description

technical field [0001] The invention belongs to the technical field of communication, and relates to the adaptive modulation of an OFDM system (OFDM, Orthogonal Frequency Division Multiplexing) and a carrier interference (CI, Carrier Interferometry) OFDM system. Background technique [0002] Adaptive modulation is to adjust the modulation mode of each sub-carrier according to the condition of each sub-channel. That is, when the sub-channel environment is good, more bits are allocated on the sub-carrier, and high-order modulation is used to obtain a higher data rate; when the sub-channel environment is poor, more bits are allocated on the sub-carrier. Small number of bits, using low-order modulation. The Greedy algorithm is an adaptive bit allocation algorithm used in OFDM or multi-carrier systems. In each iteration of the algorithm, it only allocates 1 bit, and this bit is allocated to the subcarrier that only needs to increase the minimum transmission power to maintain th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L1/00
Inventor 陈肖虎王军李少谦
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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