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Random access method utilized in orthographic frequency division multiple access (OFDM) system

A technology of orthogonal frequency division multiple access and random access, which is applied in the direction of orthogonal multiplexing system, multi-frequency code system, communication between multiple stations, etc., and can solve the network throughput of pure time slot ALOHA technology Unable to meet the requirements and other problems, to achieve the effect of large access throughput

Inactive Publication Date: 2003-12-24
武汉汉网高技术有限公司
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AI Technical Summary

Problems solved by technology

However, for OFDM cellular systems with large-capacity users, the network throughput of pure time-slot ALOHA technology cannot meet the requirements when the traffic is heavy.

Method used

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  • Random access method utilized in orthographic frequency division multiple access (OFDM) system
  • Random access method utilized in orthographic frequency division multiple access (OFDM) system
  • Random access method utilized in orthographic frequency division multiple access (OFDM) system

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Experimental program
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Embodiment Construction

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] figure 1 It is a flow chart of random access including processing at the mobile terminal and the base station. Ind is the control information that MAC indicates to initiate random access and the information required by the user for access, Res is the message that the random access module reports the access situation to the MAC layer, Ari (i=1, 2...n is the user The number of) is the access application, collision detection message and access message initiated by the user, and D1d is the downlink access control information sent by the base station. The random access processing flow is as follows:

[0030] ①. The random access mobile terminal processing module 101 of user i receives the access instruction from the MAC layer to initiate random access, and transmits the access application to the base station, and starts to monitor the downlink control message D1d a...

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PUM

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Abstract

By using the invented method, the used end in the OFDM system can complete the initial registration for logging on, the transmission of signaling in stand by state and the transmission of paroxysmal shot packet of data package. In the invention the procedure for accessing the mobile end is realized through the two steps: access trial and access message. The main characters are as following. (1) The time slots for access trial and access message are arranged independently, thus access prefixes and access messages of multiple users are not affected each other. (2) Synchronization method suitable to OFDM system is utilized. Thus, when the system treats the access procedure, the procedure of evaluating and correcting the timing and frequency deviation is carried out at same time. (3) Using CRC mode tests access conflict. Thus, the invention is a suitable random access method as well as the elementary method for evaluating the timing and frequency deviation.

Description

technical field [0001] The present invention relates to a random access method used in an OFDM cellular mobile communication system, in particular to a method for implementing a random access system for multiple users in a shared random access channel in an OFDM-based wireless cellular mobile communication system. Background technique [0002] With the rapid development of mobile communication technology and the emergence of multimedia applications, people put forward higher requirements and hopes for the wireless transmission technology of the new generation of cellular mobile communication system. At the same time, broadband OFDM (Orthogonal Frequency Division Multiplexing) as a A new way to solve the problem is getting more and more attention in the arena of the new generation cellular mobile communication system. [0003] OFDM is a parallel transmission technology. It sets K equally spaced orthogonal subcarriers on the specified frequency band. Eac...

Claims

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Application Information

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IPC IPC(8): H04B7/26H04J11/00H04L27/26H04W74/08
Inventor 郭磊吴利华付伟周宗仪朱光喜
Owner 武汉汉网高技术有限公司
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