LBT (Listen Before Talk) mechanism which synchronously takes uplink and downlink into consideration in LAA (Licensed-Assisted Access) system

A mechanism and link technology, applied in the field of LBT mechanism, can solve the problems of inflexibility, direct application, and inability to adapt to different frame structures, and achieve the effects of improving utilization efficiency, flexible burst structure, and avoiding wireless system conflicts

Active Publication Date: 2016-06-01
SHANDONG WINSPREAD COMM TECH
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Problems solved by technology

These existing solutions cannot be directly applied to the LAA system with TDD frame st

Method used

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  • LBT (Listen Before Talk) mechanism which synchronously takes uplink and downlink into consideration in LAA (Licensed-Assisted Access) system
  • LBT (Listen Before Talk) mechanism which synchronously takes uplink and downlink into consideration in LAA (Licensed-Assisted Access) system
  • LBT (Listen Before Talk) mechanism which synchronously takes uplink and downlink into consideration in LAA (Licensed-Assisted Access) system

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[0062] Example

[0063] The LBT mechanism is mainly used to compete for channels in the unlicensed frequency band. The IEEE802.11 protocol and the European ETSIEN301893 protocol make detailed regulations on the LBT mechanism used by the wireless access system working in the unlicensed frequency band. The basic idea is that the sender needs to send data Before, the wireless channel must be monitored, and data can be sent only when the channel is detected to be idle.

[0064] The existing LBT mechanism is mainly suitable for wireless systems with contention-based channel access methods, such as WIFI systems. When the senders of these wireless access systems compete for the channel through the LBT mechanism, they can immediately send data. However, for the LAA system, it is based on the LTE architecture, which uses a scheduling-based channel access method, and defines the corresponding frame structure. Downlink data (eNB sent) and uplink data (UE sent) can only be in the corresponding...

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Abstract

The invention discloses an LBT mechanism which synchronously takes an uplink and a downlink into consideration in an LAA system. The mechanism comprises following steps: designing uplink and downlink burst structures, designing a CCA (Clear Channel Assessment) detection time window, designing a channel reserved signal and designing a channel access process, wherein with respect to the step of designing the uplink and downlink burst structures, a piece of UE or an eNB each time can transmit data only in one or several sub-frames in uplink or downlink burst, specifically, it is determined by a channel access moment, the quantity of to-be-transmitted data and the maximum number of sub-frames allowed to be sent; with respect to the step of designing the CCA detection time window, different detection time windows are adopted by the uplink and the downlink; with respect to the step of designing the channel reserved signal, the step is only used for the downlink, the channel reserved signal is designed by taking a CRS as the basis according to the symbol cycle of the OFDM; with respect to the step of designing the channel access process, with respect to the uplink, a channel access process with a self-adaptive backspacing function is adopted; and with respect to the downlink, a channel access process without a function is adopted. The scheme of the invention is applicable to various TDD frame structures and can coexist with unauthorized frequency bands in a WIFI system friendly; and moreover, relatively high channel utilization efficiency can be obtained.

Description

Technical field [0001] The present invention relates to the research field of wireless access systems, in particular to an LBT mechanism in the LAA system that simultaneously considers the uplink and downlink. Background technique [0002] LAA (Licensed-Assisted Access) system is an LTE system for accessing unlicensed frequency bands assisted by licensed frequency bands, and typically works in 5 GHz unlicensed frequency bands. By connecting LTE to unlicensed frequency bands, LAA can effectively solve the problem of LTE system spectrum tension in licensed frequency bands, especially in hotspots with large traffic. By connecting LTE to unlicensed frequency bands, it can effectively connect LTE The offloading of services to unlicensed frequency bands greatly improves the ability of LTE operators to provide services. [0003] An important issue that needs to be solved when LTE accesses unlicensed frequency bands is fair and effective coexistence with WIFI and other wireless systems wo...

Claims

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Application Information

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IPC IPC(8): H04W74/08
CPCH04W74/0816
Inventor 刘圣海吴汉光温庆超
Owner SHANDONG WINSPREAD COMM TECH
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