Method for detecting cyclic prefix length in time division duplex system

Abstract

The invention discloses a method for detecting the cycle prefix length in a time division duplex system, which comprises the steps of: broadcasting synchronization information by a system through a base station, wherein the synchronization information comprises a master synchronization signal and an auxiliary synchronization signal, and at least one orthogonal frequency division multiplexing (OFDM) symbol is arranged between the master synchronization signal and the auxiliary synchronization signal; capturing synchronization information of the system by a terminal unit to detect the master synchronization signal and determine the position of the master synchronization signal; obtaining two auxiliary synchronization signal sequences from the synchronization information of the system by the terminal unit based on the determined master synchronization signal position and respectively in accordance with conditions of short cycle prefix and long cycle prefix; and carrying out correlation of the obtained two auxiliary synchronization signal sequences respectively with an auxiliary synchronization signal standard sequence determined in advance and judging the length of the cycle prefix based on relevant result, both by the terminal unit. By adopting the technical proposal, the method for detecting the cycle prefix length in the time division duplex system can acquire better detecting property.

Description

technical field [0001] The invention relates to the field of information transmission of a wireless communication system, in particular to a method for detecting the length of a cyclic prefix in a Time Division Duplex (TDD) system. Background technique [0002] At present, Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier transmission mode, because of its strong ability to resist inter-symbol interference (ISI), high bandwidth utilization, and simple implementation, it has been successfully implemented. Applied in the long term evolution system (LTE). [0003] In an OFDM system, an OFDM symbol is composed of multiple sub-carrier signals superimposed, and each sub-carrier is distinguished by orthogonality, so ensuring this orthogonality is crucial for OFDM systems. In order to eliminate the interference between different subcarriers (ISI) caused by the destruction of the orthogonality between subcarriers caused by multipath, the OFDM system adds a guard in...

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Problems solved by technology

[0007] In the current LTE system configuration, the pilot does not occupy the entire frequency band, and only occupies a small part of the subcarriers to meet its demodulation requirements at the receiving end, which also means that the CP length used in CP length detection The length of the pilot sequence is short, which will affect the correlation performance, because the length of the sequence for correlation directly affects the quality of the correlation performance. If the sequence is long, the correlation performance will be good, and if the sequence is short, the correlation performance will be poor. In addition, if the pilot sequence is short, its The correlation power value is low, and the noise immunity performance is also poor, so the detection performance of this method is poor

[0008] It can be seen that due to the relatively short length of the pilot sequence used for correlation, the method of using the pilot to detect the length of the cyclic prefix has the problem of poor detection performance

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