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Framing method are synchronous wireless system therewith

A wireless system and framing technology, applied in the transmission system, multi-carrier system, code division multiplexing system, etc., can solve the problems of increasing system complexity, orthogonal property destruction, interference, etc.

Inactive Publication Date: 2002-11-06
LINKAIR COMM
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

This greatly increases the complexity of the system
Existing CDMA systems use pseudo-random spreading codes that result in non-zero interference
Even when using orthogonal spreading codes such as Walsh codes that give zero interference, the orthogonality property is corrupted when there are multipath signals from the same remote unit or the signals from different remote units are out of sync, resulting in Interference Between Different Signals

Method used

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  • Framing method are synchronous wireless system therewith
  • Framing method are synchronous wireless system therewith
  • Framing method are synchronous wireless system therewith

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Embodiment Construction

[0030] As shown in Figure 1, the preferred embodiment of the communication system of the present invention comprises a cellular system comprising a plurality of cells serving a geographic area, a base station in each cell providing downlink signals to remote units in the cell , multiple remote units in each cell. Figure 2 shows a base station and multiple remote units in a cell. The base station comprises transmitters and receivers and suitable processors for carrying out the method of the invention. Each of the plurality of remote units includes a transmitter, a receiver, and an appropriate processor for carrying out the methods of the present invention.

[0031] As a preferred embodiment, the present invention can use the Advanced Mobile Phone System (AMPS) or Personal Communication System (PCS) frequency band with Frequency Division Duplex (FDD). As a preferred embodiment of the present invention, FIG. 3 illustrates the frame structure of 20 milliseconds for the downlink ...

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Abstract

A framing method and its synchronous wireless system, wherein the method includes the step of: dividing the data flow into frames according to the frame length, wherein the number of subframes in each frame can be determined by the periodicity of the selected LA code. Each subframe is formed by a plurality of time slots, wherein the number of time slots can be determined by the number of pulses of the LA code, and the length of the time slot varies with the pulse interval of the LA code. and fill each slot by modulating with a selected orthogonal spreading code. Different base stations from different adjacent cells should be assigned different LA-CDMA codes, so that the adjacent cell interference can be reduced. But in adjacent cells, the same spreading code can be assigned. Therefore, the requirements on the number of spreading codes and the length of spreading codes are greatly reduced.

Description

technical field [0001] The present invention generally relates to a framing method and a wireless system thereof, in particular to a framing method for the physical layer and a synchronous wireless system thereof, and more particularly to a method for reducing interference and combining code division multiple access and time division multiple access Systems and methods for addressing. Background technique [0002] In a CDMA system, each remote unit modulates the data it transmits to the base station with a spreading code unique to that remote unit. Spread spectrum, coded signals transmitted by different remote units may overlap in time and frequency. When these signals arrive at the receiving base station, the data transmitted by the remote unit is obtained by correlating the received signal with the remote unit's unique spreading code. [0003] We all know that the capacity of CDMA system is limited by interference. These interferences include intersymbol interference (I...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J13/00H04J13/18H04L27/34
CPCH04J13/18H04L27/34
Inventor 李道本高海阳何绍明张永生陈卫东邓元华
Owner LINKAIR COMM
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