TOA training symbol construction of indoor OFDM system and method and device for estimating TOA

A technology for training symbols and symbols, applied in the field of communication, can solve the problems of increasing algorithm complexity, difficult to use, affecting system resolution, estimation accuracy, etc.

Inactive Publication Date: 2011-06-29
XIDIAN UNIV
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  • Abstract
  • Description
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Problems solved by technology

[0034] (2) Information such as channel autocorrelation matrix and noise variance are required to be known before TOA estimation, but such information is usually not easy to obtain;
[0035] (3) In TOA estimation, it is necessary to calculate the inverse operation of multiple matrices and the multiplication of multiple matrices, and some require complex operations such as matrix singular value decomposition, which has high complexity and the logarithmic value τ n It is also necessary to search within a certain range. The size of the search step directly affects the system resolution and estimation accuracy. The smaller the step size is, the resolution and accuracy will be improved, but the complexity of the algorithm will increase sharply;
[0036] (4) Due to the high conditions of use and complexity, it is difficult to use in actual systems

Method used

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  • TOA training symbol construction of indoor OFDM system and method and device for estimating TOA
  • TOA training symbol construction of indoor OFDM system and method and device for estimating TOA
  • TOA training symbol construction of indoor OFDM system and method and device for estimating TOA

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Embodiment Construction

[0104] 1. Construction of a training symbol used for TOA estimation and an OFDM frame format containing the training symbol.

[0105] In an OFDM system, if the maximum delay spread of the channel is τ max , the sampling time interval of the system is T s , the number of subcarriers is N, and the effective duration of the symbol is T, then in order to overcome the influence of ISI, the length of the cyclic prefix is ​​usually selected T CP = GT s ≥τ max ,make

[0106]

[0107] In the formula: Represents rounding, N represents the length of the OFDM symbol, and G represents the length of the cyclic prefix of the OFDM symbol; in order to facilitate application in the OFDM system, the present invention selects M as an integer power of 2.

[0108] For convenience, the OFDM training symbols used for TOA estimation are referred to as TOA training symbols for short in the present invention.

[0109] The construction of the TOA training symbols can be performed in the frequen...

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Abstract

The invention comprises: first off, creating the training symbol used for making TOA estimation; using the TOA training symbol to compose OFDM frame format in order to make TOA estimation. Said TOA estimation comprise: 1) at receiving end, extracting TOA training symbol in order to make pretreatment; removing the effect of time-delay on other multi paths except first path in order to make the transmission factor on each sub -channel identical; 2) making FFT transformation for the pretreated data; 3) making the cross correlation operation for the FFT transformed data and the frequency domain basic data of training symbol; 4) by the phase of cross correlation function, estimating the arrival timeTau0 from the first path of transmitted signal to the receiving antenna.

Description

technical field [0001] The invention belongs to the communication field and relates to OFDM systems, in particular to the construction of TOA training symbols and the estimation of TOA in indoor OFDM systems, which can be used in indoor positioning systems. Background technique [0002] As we all know, due to the occlusion of buildings, it is not possible to use a satellite positioning system, such as GPS, for positioning in an indoor environment, but to use indoor positioning. However, due to the complex indoor environment, there are abundant multipath components, and there are two propagation conditions of visible path LOS and non-visible path NLOS, it is required that indoor positioning must have higher positioning than outdoor positioning in a limited environment size. precision. [0003] Ultra-wideband UWB indoor positioning technology has the advantages of strong multipath resolution and high positioning accuracy, and is currently a hot spot in indoor positioning rese...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26H04L25/02
Inventor 任光亮倪浩张会宁常义林张辉
Owner XIDIAN UNIV
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