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Frame synchronization detection method and device for OFDM system

A technology of orthogonal frequency division and detection method, which is applied in the field of wireless communication, can solve problems such as detection performance degradation, failure, and destruction of three-segment pseudo-periodic characteristics, and achieve the effect of solving synchronization problems and realizing OFDM frame synchronization

Inactive Publication Date: 2008-08-13
SHANGHAI RES CENT FOR WIRELESS TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method does have better performance without considering the inter-sector interference, but when the sector interference is more obvious, because the sector interference destroys the three-segment pseudo-periodic characteristics of the preamble, the detection performance of this method will be lower. significantly reduced, and in extreme cases even fails

Method used

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  • Frame synchronization detection method and device for OFDM system
  • Frame synchronization detection method and device for OFDM system
  • Frame synchronization detection method and device for OFDM system

Examples

Experimental program
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Effect test

Embodiment 1

[0045] Embodiment 1: Realize the frame synchronization detection based on the preamble conjugate symmetry characteristic by using FPGA.

[0046] Such as image 3 As shown, two receiving buffers Rx Buff1 and Rx Buff2 are set, both of length 2w+1 (w is the size of the conjugate correlation window, satisfying w≤(FFT_size) / 2).

[0047] The OFDM data signal is serially input into the receiving buffer Rx Buff1 after being converted by an analog-to-digital converter (AD Converter, ADC for short). When Rx Buff1 is full, take the data r(d) in the buffer as the axis of symmetry for mirror symmetry operation, and store the operated data in Rx Buff2. Usually, because the actual operation only uses half or less of the data in the buffer, the buffer Rx Buff2 in the present invention can also be replaced by the rest of the Rx Buff1. In the present invention, for convenience of description, two buffers are still used.

[0048] Use the data in the buffers Rx Buff1 and Rx Buff2 to perform fr...

Embodiment 2

[0054] Embodiment 2: Utilize DSP to realize frame synchronization detection based on the preamble conjugate symmetry characteristic.

[0055] The OFDM data signal is converted by the ADC and placed in the memory. At each calculation, the data of length 2w+1 is taken from the memory and placed in the register Rx Buff1, and then the Rx Buff1 is mirrored with the intermediate data as the axis of symmetry. The operated data is stored in Rx Buff2. The registers Rx Buff1 and Rx Buff2 are structured with image 3 The receive buffer structure shown is the same.

[0056] Then use the data in Rx Buff1 and Rx Buff2 to perform downlink frame detection calculation according to the formulas (1)-(4). The specific process is the same as that in Embodiment 1, so it will not be repeated.

[0057] It should be noted that the difference between the calculation method in Embodiment 2 and the method using FPGA calculation in Embodiment 1 is mainly that FPGA can perform parallel operations, so rea...

Embodiment 3

[0058] Embodiment 3: Using FPGA+DSP to realize frame synchronization detection based on the preamble conjugate symmetry characteristic.

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Abstract

A frame synchronization detecting method in an orthogonal frequency division multiplex system comprises: conjugating correlation calculation to data signals in a fore and aft conjugate correlation window of data signal in a data signal sequence to obtain a correlation calculation accumulate result by accumulating; calculating an average energy of data signals in the fore and aft conjugate correlation window; taking a metric value of a data signal as a ratio between the correlation calculation accumulate result and the average energy, and in a detecting period, such as in a length of 1.5 frame, determining a frame starting time based on a data signal with a metric value maximal. The method, based on a character that predecessor using BPSK modulate conjugates symmetry, performs a frame synchronization detect, solves the synchronization problem in the orthogonal frequency division multiplex system.

Description

technical field [0001] The present invention relates to data transmission technology in the field of wireless communication, in particular to a frame synchronization detection method and device in an Orthogonal Frequency Division Multiplexing ("OFDM" for short) system. Background technique [0002] In the development of wireless communication technology, the lack of wireless spectrum resources and the fading of transmission signals caused by multipath and time-varying characteristics of wireless channels have always restricted the further development of wireless communication technology. Correspondingly, OFDM technology has become a hotspot in wireless communication technology research because of its high spectrum utilization rate and its ability to overcome the multipath characteristics of wireless channels well. [0003] OFDM technology was first proposed in the mid-1960s, when it was mainly used in military wireless high-frequency communication systems. This technology p...

Claims

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Application Information

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IPC IPC(8): H04L7/04H04L27/26H04L12/28H04J11/00
Inventor 贠超
Owner SHANGHAI RES CENT FOR WIRELESS TECH
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