Unauthorized random access method in multi-cell large-scale MIMO system

A random access, large-scale technology, applied in transmission systems, digital transmission systems, radio transmission systems, etc., can solve the problems of short messages, large number of terminals, and high delay in message transmission, achieve strong practical feasibility and improve connection. The effect of input efficiency and broad application prospects

Active Publication Date: 2021-09-21
NANJING UNIV OF POSTS & TELECOMM
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Considering that there will be a large number of machine-type communications in future wireless communication systems, and such machine-type communications usually have the characteristics of a large number of terminals, short messages, and short delays, traditional authorization-based random access schemes are limited. Due to its characteristics of high signaling overhead and high message transmission delay, it is not applicable

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  • Unauthorized random access method in multi-cell large-scale MIMO system
  • Unauthorized random access method in multi-cell large-scale MIMO system
  • Unauthorized random access method in multi-cell large-scale MIMO system

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Embodiment Construction

[0048] Such as figure 1 As shown, the present invention discloses an unauthorized random access method in a multi-cell massive MIMO system. The method specifically includes the following steps:

[0049] S1. A pilot multiplexing mechanism is established by using a frequency multiplexing mode, so that adjacent cells select different groups of pilots to realize pilot orthogonality.

[0050] Further, the steps of S1 can be further refined as follows.

[0051] S11. There are L cells, each cell has N users, the total length of the pilot is t, and there are t orthogonal pilots in total;

[0052]S12. Dividing the pilots into a group, the number of orthogonal pilots in each group is t / a, where a is the pilot multiplexing factor;

[0053] S13. Make adjacent a cells select pilots of different groups, so that pilots are orthogonal.

[0054] S2. According to the pilot reuse factor, the number of users in the cell, and the base station antenna, etc., with the goal of maximizing the avera...

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Abstract

The invention discloses an unauthorized random access method in a multi-cell large-scale MIMO system, and the method comprises the following steps: S1, establishing a pilot frequency multiplexing mechanism by utilizing a frequency multiplexing mode, and enabling adjacent cells to select different groups of pilot frequencies to realize pilot frequency orthogonality; S2, calculating an optimal pilot frequency length and a user random access back-off probability by taking maximization of the average spectrum efficiency of each cell as a target; S3, enabling each user to perform the random delay activation according to the backoff parameter broadcasted by the base station, enabling the activated user to randomly select a pilot frequency from the pilot frequency pool of the cell and sending the pilot frequency to the base station; S4, enabling the base station to identify the cross-cell conflict users by using the signal intensity difference, determining that the access of the unidentified users fails, and waiting for the next time slot to initiate access again. According to the method, the user access efficiency in a massive user scene can be remarkably improved, the overall spectrum efficiency of the system is greatly improved, and the method has relatively high practical feasibility and can be practically applied to an actual communication scene.

Description

technical field [0001] The invention relates to an unauthorized random access method in a multi-cell massive MIMO system, belonging to the technical field of wireless communication. Background technique [0002] In recent years, with the rapid development of wireless communication technology, more and more researchers in the industry have begun to try to build a feasible future wireless communication system architecture. Considering that there will be a large number of machine-type communications in future wireless communication systems, and such machine-type communications usually have the characteristics of a large number of terminals, short messages, and short delays, traditional authorization-based random access schemes are limited. Due to its high signaling overhead and high message transmission delay, it is not applicable. In view of this, the unlicensed random access, which allows the terminal to directly transmit its pilot and uplink data to the base station, has at...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04W74/08H04L5/00H04B7/0413
CPCH04W74/0833H04W74/085H04L5/0048H04B7/0413Y02D30/70
Inventor 张琦方莹莹张军
Owner NANJING UNIV OF POSTS & TELECOMM
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