摘要
在VoWLAN(VoIP over WLAN)系统中,当周期性语音业务与随机性数据业务混合传输时,面临着信道能容纳的话路数少、语音业务与数据业务获得信道的机会不可控等问题。IEEE802.11e协议在传输周期的无竞争期(CFP)采用混合协调功能(HCF)来解决语音业务QoS问题。研究在IEEE802.11e的HCF机制基础上,对媒质接入控制(MAC)层进行了改进,对CFP时段的上行周期性语音采用无竞争预约排队信道接入(CFRQCA)机制取代HCF受控信道接入(HCCA)方式,在CFP时段的下行语音接入采用M-M(Multicast-Multiplexing)机制;为了协调语音业务与数据业务的接入机会,论文中还提出了一种基于业务流量监测的接入机会自适应调度算法(AOASA);理论分析和仿真表明,无竞争预约排队机制和接入机会自适应调度算法能显著提高信道容纳的话路数。
When periodic voice service and random data service are transmitted together,VoWLAN（VoIP over WLAN） system faces the problem that the supported voice calls are less and the opportunity for voice service and data service to access channels is uncontrollable.In CFP time zone of transmission period,IEEE802.11e protocol adopts Hybrid Coordination Function（HCF） to solve the QoS problem of voice service.In this paper,IEEE 802.11e Medium Access Control（MAC） layer is improved based on HCF Mechanism.Contention-Free Reservation Queuing Channel Access（CFRQCA） mechanism is used to replace HCF Controlled Channel Access（HCCA） style in uplink voice service during CFP time zone,and M-M（Multicast-Multiplexing） mechanism is used in downlink voice service during CFP time zone.Meanwhile,to coordinate the access opportunity of voice service and data service,Access Opportunity Adaptively Scheduling Algorithm（AOASA） based on service traffic measuring is presented.Theoretical analysis and simulation show that CFRQCA and AOASA can remarkably increase the number of supported voice calls.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2011年第7期1660-1668,共9页
Chinese Journal of Scientific Instrument
基金
国家863基金(No.2009AA01Z241)资助项目
