Variable-bandwidth OFDM (Orthogonal Frequency Division Multiplexing) transmitter and receiver

Abstract

The invention belongs to the field of wireless communication, and relates to a variable-bandwidth OFDM (Orthogonal Frequency Division Multiplexing) transmitter and receiver which are used for transmitting and receiving the OFDM signals composed of effective information symbols and cyclic prefixes. The transmitter 100 comprises a segment manager 101, a symbol adding unit 102, a mapping unit 103, an OFDM signal generation unit 104, a frame length regulation unit 105, a carrier regulation unit 106 and a carrier amount storage unit 107; the receiver 202 comprises a cyclic prefix detection unit 201, an FFT (Fast Fourier Transform) unit 202, a data screening unit 203, a data post-processing unit 204, a carrier estimation unit 205, a channel idle bandwidth estimation unit 206, a carrier information storage unit 207 and a carrier change decision-making unit 208. The transmitter can be used for dynamically regulating the amount of carriers according to the communication bandwidth change feed-back information provided by the receiver, so as to control the communication bandwidth and dynamically change the information bit transmission rate.

Description

technical field [0001] The invention belongs to the field of radio communication, and in particular relates to a variable bandwidth OFDM transmitter and receiver for sending and receiving frame OFDM signals composed of effective information symbols and cyclic prefixes. Background technique [0002] OFDM technology is a transmission scheme that utilizes multiple orthogonal carrier frequencies to send signals. The serial-to-parallel conversion of the high-speed data stream in the system makes the duration of the data symbol on each subcarrier increase relatively, thereby effectively reducing the intersymbol interference (ISI) caused by the time dispersion of the wireless channel, and making the equalizer in the receiver complexity is reduced. All subcarriers within the bandwidth of OFDM transmitted signals are orthogonal to each other, so the spectrum can overlap with each other, which can maximize the use of spectrum resources. When the number of subcarriers is large, the sp...

AI Technical Summary

Problems solved by technology

Although the bandwidth of this system is variable, it still cannot effectively eliminate the influence of adjacent channel interference on the edge subcarriers of this channel because its bandwidth only changes with the change of the data transmission rate of the source, nor can it improve bandwidth utilization.

In addition, the change of the bandwidth needs to be repeatedly confirmed by the transmitter and the receiver. The process is very complicated, and the transmission of the confirmation information itself also has the risk of being interfered.

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