License assisted access(LAA) was proposed as a solution to the challenge of satisfying high throughput requirement in cellular network with limited licensed band. LAA uses long term evolution(LTE) carrier aggregation ...License assisted access(LAA) was proposed as a solution to the challenge of satisfying high throughput requirement in cellular network with limited licensed band. LAA uses long term evolution(LTE) carrier aggregation technique to combine licensed and unlicensed bands, specifically 5 GHz Wi Fi band, in order to achieve high data rates. However, LAA has several critical concerns for services provision on 5 GHz unlicensed band. In this article, an overview of the techniques concerning the coexistence of LTE and Wi Fi on the same unlicensed band is presented. We first present several general approaches including power control of LTE evolved Node B(e NB), carrier selection, LTE duty cycling, self clear to send(CTS) and request to send/CTS(RTS/CTS), and listen before talk(LBT). Then, we focus on LBT techniques for LAA-Wi Fi coexistence and discuss how LBT based coexistence solutions can dynamically respond to the variations in network load and ensure fair coexistence in a distributed manner. Based on the LBT mechanism, we also present a fairness-aware LAA-WiF i coexisting scheme with TXOP(transmitted in a single transmission opportunity) backoff for LAA e NB. Finally, the performances of various LBT solutions for LAA-Wi Fi coexistence are evaluated using Markov chain analytical model.展开更多
无线上网正在成为一种时尚．但现在最火爆的Wi—Fi技术必须在特定的无线网络环境下才可以使用．因此要想真正做到随时随地无线上网．笔记本电脑+GPRS”才是目前最佳的选择。而现在通过GPRS上网通常有两种方式：一是GPRS手机通过数据线...无线上网正在成为一种时尚．但现在最火爆的Wi—Fi技术必须在特定的无线网络环境下才可以使用．因此要想真正做到随时随地无线上网．笔记本电脑+GPRS”才是目前最佳的选择。而现在通过GPRS上网通常有两种方式：一是GPRS手机通过数据线或红外线接口与笔记本电脑连接．这种方式在兼容性和稳定性方面有所欠缺．而第二种方式是直接通过GPRS USB MODEM无线上网．其最大的优点是不需要具备GPRS功能的手机，即插即用。展开更多
基金supported in part by Joint Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) and Research Grants Council Earmarked Research Grants (RGC ERG) with Grant 20130142140002National Science Foundation of China with Grants 61531011 and 61471163Major Program of National Natural Science Foundation of Hubei in China with Grant 2016CFA009
文摘License assisted access(LAA) was proposed as a solution to the challenge of satisfying high throughput requirement in cellular network with limited licensed band. LAA uses long term evolution(LTE) carrier aggregation technique to combine licensed and unlicensed bands, specifically 5 GHz Wi Fi band, in order to achieve high data rates. However, LAA has several critical concerns for services provision on 5 GHz unlicensed band. In this article, an overview of the techniques concerning the coexistence of LTE and Wi Fi on the same unlicensed band is presented. We first present several general approaches including power control of LTE evolved Node B(e NB), carrier selection, LTE duty cycling, self clear to send(CTS) and request to send/CTS(RTS/CTS), and listen before talk(LBT). Then, we focus on LBT techniques for LAA-Wi Fi coexistence and discuss how LBT based coexistence solutions can dynamically respond to the variations in network load and ensure fair coexistence in a distributed manner. Based on the LBT mechanism, we also present a fairness-aware LAA-WiF i coexisting scheme with TXOP(transmitted in a single transmission opportunity) backoff for LAA e NB. Finally, the performances of various LBT solutions for LAA-Wi Fi coexistence are evaluated using Markov chain analytical model.
文摘无线上网正在成为一种时尚．但现在最火爆的Wi—Fi技术必须在特定的无线网络环境下才可以使用．因此要想真正做到随时随地无线上网．笔记本电脑+GPRS”才是目前最佳的选择。而现在通过GPRS上网通常有两种方式：一是GPRS手机通过数据线或红外线接口与笔记本电脑连接．这种方式在兼容性和稳定性方面有所欠缺．而第二种方式是直接通过GPRS USB MODEM无线上网．其最大的优点是不需要具备GPRS功能的手机，即插即用。
