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Enhanced block scrambling code division multiple access (BSCDMA) method

An access method and mixed code technology, applied in the multi-frequency code system and other directions, can solve problems such as the reduction of frequency band utilization, and achieve the effects of suppressing multi-path interference, low bit error rate, and strong anti-multi-access interference.

Inactive Publication Date: 2015-04-29
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the addition of CP, the frequency band utilization will be reduced

Method used

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  • Enhanced block scrambling code division multiple access (BSCDMA) method
  • Enhanced block scrambling code division multiple access (BSCDMA) method
  • Enhanced block scrambling code division multiple access (BSCDMA) method

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specific Embodiment approach 1

[0048] Specific implementation mode 1. Combination Figure 1 to Figure 10 Describe this specific implementation mode, the enhanced block hybrid code division multiple access method, the enhanced block hybrid code division multiple access method, which is realized based on the OFDM system,

[0049] The signal transmission method of the transmitting end in the downlink of the system:

[0050] When the i-th symbol of the user is sent, the following operations are performed:

[0051] Step A1, spreading the i-th symbol using a Hadamard sequence, and performing serial / parallel conversion on the spread data to obtain M channels of parallel data;

[0052] Step A2, multiplying the M parallel data obtained in step A1 with the M subcarriers respectively to obtain M processed data; the M subcarriers are discrete data output by M code sequences through FFT;

[0053] Step A3, performing parallel / serial conversion on the M channels of processed data obtained by each user in step A2 to obta...

specific Embodiment approach 2

[0190] Embodiment 2. The difference between this embodiment and the embodiment is that the serial signal obtained by each user in step A3 can be divided into a real part and an imaginary part for digital / analog conversion, carrier modulation and bandpass filtering respectively. , and then added together to form a band-pass filtered signal.

[0191] EBS-CDMA is feasible in theory, but if it is put into practical engineering application, there may be certain difficulties in some specific links. For example, the output of FFT contains a complex exponential function. In order to make the system have practical significance, the following describes specific implementation methods.

[0192] Since there is no difference in the implementation of EBS-CDMA in the uplink and downlink, the following only describes the sending end and receiving end of the uplink.

[0193] The system structure of the sending end: first, the implementation mode of the EBS-CDMA sending end is described, see ...

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Abstract

The invention provides an enhanced block scrambling code division multiple access (BSCDMA) method, relating to a multiple access method and aiming to overcome the defect of utilizing cyclic prefix (CP) to inhibit multipath interface in the orthogonal frequency division multiplexing (OFDM) system. At a transmitting terminal of a down link, data of the user are subject to frequency spread by adopting a Hadamard sequence and then are modulated and output. At a receiving terminal of the down link, the received signals are demodulated, are subjected to inverse transformation with the transmitting terminal and then are judged and output. At a transmitting terminal of an up link, data of the user are subject to frequency spread by adopting the Hadamard sequence and then are modulated and output. At a receiving terminal of the up link, a base station demodulates the received signals, carries out inverse transformation on the signals with the transmitting terminal and then judges and outputs the signals. The invention provides a new multiple access system model, overcomes the defect of utilizing CP to inhibit multipath interference in the OFDM system and can inhibit multipath interference while substantially improving the frequency band utilization rate. The method is suitable for wireless communication.

Description

technical field [0001] The invention relates to a multiple access method. Background technique [0002] In an Orthogonal Frequency Division Multiplexing (OFDM) system, to overcome multipath interference, it is necessary to add a Cyclic Prefix (CP) to the transmitted symbols, and the length of the CP is also strictly limited. , if the length of the CP is less than the maximum delay, it will cause very serious inter-symbol interference (Inter-Symbol Interference, ISI) and inter-carrier interference (Inter-Carrier Interference, ICI). Due to the addition of the CP, the utilization rate of the frequency band will be reduced. Contents of the invention [0003] The present invention aims to overcome the shortcoming of using CP to suppress multi-path interference in the OFDM system, thereby providing an enhanced block hybrid code division multiple access method. [0004] Enhanced block hybrid code division multiple access method, which is realized based on OFDM system, [0005]...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26
Inventor 陈晓华刘喜庆林凡孟维晓
Owner HARBIN INST OF TECH
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