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Method and device for determining cyclic prefix mode and timing with orthogonal frequency division multiplexing symbol

An orthogonal frequency division and cyclic prefix technology, applied in the direction of multi-frequency code system, etc., can solve the problems of non-existence of CP mode and OFDM symbols

Inactive Publication Date: 2012-08-01
ST ERICSSON SEMICON BEIJING
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0011] However, there is no technical solution for determining the CP mode and OFDM symbol timing in the prior art, which makes it impossible to detect the primary / secondary synchronization signal in the frequency domain

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  • Method and device for determining cyclic prefix mode and timing with orthogonal frequency division multiplexing symbol
  • Method and device for determining cyclic prefix mode and timing with orthogonal frequency division multiplexing symbol
  • Method and device for determining cyclic prefix mode and timing with orthogonal frequency division multiplexing symbol

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Embodiment Construction

[0036] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0037] In the LTE system, each frame includes 10 subframes, each subframe includes two time slots, and the length of each time slot is 0.5 ms. As mentioned above, in normal CP mode, 7 OFDM symbols can be accommodated in one slot, and in extended CP mode, 6 OFDM symbols can be accommodated in one slot.

[0038] There are two standards in the LTE system: FDD (Frequency Division Duplex) and TDD (Time Division Duplex).

[0039] For the FDD mode, the uplink and downlink signals use different frequencies, and the signals received by the terminal are all downlink signals from the base station side. In the normal CP mode, the distribution position of the CP data in the received data is repeated with a period of time slots, that is, the repetition period of the...

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Abstract

The invention discloses a method and a device for determining a cyclic prefix (CP) mode and timing with orthogonal frequency division multiplexing (OFDM) symbols. The method comprises the following steps: firstly, carrying out conjugate multiplication on each segment of data in received data and data of the segment of data after delaying NFFT to obtain an r'''m sequence; secondly, utilizing a preset repetition period Nperiod as an interval to extract data from the r'''m sequence at equal intervals for accumulating, so as to obtain an r''m sequence; thirdly, dividing CP windows in the r''m sequence aiming at a normal CP mode an expansion CP mode respectively, accumulating energy in each CP window and determining an alternative initial position of the OFDM symbols by detecting the peak value of the accumulated result; and finally, determining the CP mode aiming at the peak value determined by the normal CP mode and the peak value determined by the expansion CP mode, and outputting the initial position of corresponding OFMD signals. By applying the invention, the CP mode and the initial position of the OFDM symbols can be determined, thereby helping a terminal to realize master / slavesynchronous signal detection in frequency domain.

Description

technical field [0001] The present invention relates to long-term evolution (LTE) technology, in particular to a method and device for determining cyclic prefix (CP) mode and orthogonal frequency division multiplexing (OFDM) symbol timing. Background technique [0002] The LTE system is a wireless communication system based on OFDM technology. An important feature of the OFDM system is to introduce CP to avoid inter-symbol interference caused by multipath, that is, a symbol (the length of the symbol is N FFT ) tail data (the length of the data is N CP ) is copied to the head of the symbol to form a new length N FFT +N CP OFDM symbols. [0003] The introduction of the cyclic prefix makes the OFDM symbol have such characteristics, that is, a part of the data (namely: CP) follows a certain interval (N FFT ) to repeat. [0004] In the LTE system, the CP has two modes: normal mode and extended mode. [0005] For the normal mode, the CP length is relatively short, and 7 OFDM...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26
Inventor 许百成
Owner ST ERICSSON SEMICON BEIJING