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Method for estimating multi-path time delay for multi-user orthogonal frequency division multiplexing system

An orthogonal frequency division, multi-user technology, applied in the direction of multi-frequency code system, baseband system components, etc., can solve the problems that the estimation accuracy of multipath time delay is quite difficult, and the OFDM system cannot be directly used, so as to ensure multiple Effects of multipath delay estimation accuracy and precise multipath delay estimation accuracy

Inactive Publication Date: 2006-05-24
BEIJING UNIV OF POSTS & TELECOMM
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Problems solved by technology

However, the OFDM system is very different from the DS-CDMA system, so the above multipath delay estimation scheme cannot be directly applied to the OFDM system
Since the uplink signals in the OFDM system are mostly asynchronous, coupled with the influence of multiple users, it is quite difficult to ensure the accuracy of multipath delay estimation

Method used

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  • Method for estimating multi-path time delay for multi-user orthogonal frequency division multiplexing system
  • Method for estimating multi-path time delay for multi-user orthogonal frequency division multiplexing system
  • Method for estimating multi-path time delay for multi-user orthogonal frequency division multiplexing system

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Embodiment Construction

[0021] The preamble design and estimation method of the multipath time delay estimation provided by the invention is carried out in one time slot, and the multipath time delay estimation of the multi-user OFDM system is realized.

[0022] figure 1 It is a block diagram of the OFDM system used in the present invention and a schematic diagram of the transmission time slot structure. It can be seen that the information processing flow of the whole system, wherein the multipath time delay estimation preamble design scheme determines the specific structure of the preamble sequence at the sending end, and the multipath time delay estimation is then It is done between timing frequency synchronization and channel estimation at the receiver. At the same time, it can be seen that the transmission time slot includes preamble symbols, and the preamble symbols are used for multipath delay estimation, as well as timing and frequency synchronization. The multipath delay information can simpl...

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Abstract

Sending end executes steps: carrying out time slicing process for the leading sequence of signals in multiple users so that leading sequences of different users use different time slice of a symbol of orthogonal frequency division multiplex (FDM); after carrying out time slicing process for leading sequences, carrying out inverse Fourier transform for the processed leading sequences, then sending out processed result. The receiving end executes steps: carrying out correlation process between local sequence and the received leading sequences; selecting value of window, and reserving correlation values within window of symbol of orthogonal FDM; selecting L pieces of relevant positions of time delay from largest value, where L smaller than or equal to detectable number of path in a channel; or positions of time delay relevant correlation above threshold as information for estimating positions of time delay. Thus, estimation of time delay for multiple users is obtained.

Description

technical field [0001] The invention relates to a multi-path time delay estimation preamble sequence design and estimation method suitable for multi-user Orthogonal Frequency Division Multiplexing (OFDM) system, which is used for accurate estimation of multi-path channel time delay value. Background technique [0002] OFDM can overcome the frequency selective fading of the channel. It has been successfully applied to wireless local area network, digital broadcasting and fixed local wireless access system, and it is one of the most promising technologies in the super three-generation mobile communication system. [0003] Channel estimation is a key technology in the application research of OFDM system, multipath delay estimation of fading channel is helpful to simplify the complexity of channel estimation in the system. So far, methods for multipath delay estimation in OFDM systems are obviously lacking. Although a variety of multipath delay estimation schemes for DS-CDMA sy...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02H04L27/26
Inventor 张建华张平刘若菊徐国鑫刘宝玲
Owner BEIJING UNIV OF POSTS & TELECOMM
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