基于IEEE802.11e标准,充分考虑混合式协调功能控制信道访问机制(Hybrid Coordination Function Controlled Channel Access,HCCA)的QoS(Quality of Service)参数,提出一个HCCA软件模拟架构;根据此架构,利用NS2网络仿真工具搭建一个功能...基于IEEE802.11e标准,充分考虑混合式协调功能控制信道访问机制(Hybrid Coordination Function Controlled Channel Access,HCCA)的QoS(Quality of Service)参数,提出一个HCCA软件模拟架构;根据此架构,利用NS2网络仿真工具搭建一个功能完整且易于实施的HCCA平台,并结合资源预留方案对平台的有效性和合理性进行仿真验证。展开更多
The mobile ad hoc network (MANET) with infrastructure networks (hybrid networks) has several practical uses. The utility of hybrid network is increased in real time applications by providing some suitable quality of s...The mobile ad hoc network (MANET) with infrastructure networks (hybrid networks) has several practical uses. The utility of hybrid network is increased in real time applications by providing some suitable quality of service. The quality thresholds are imposed on parameters like end-to-end delay (EED), jitter, packet delivery ratio (PDR) and throughput. This paper utilizes the extended ad hoc on-demand distance vector (AODV) routing protocol for communication between ad hoc network and fixed wired network. This paper also uses the IEEE 802.11e medium access control (MAC) function HCF Controlled Channel Access (HCCA) to support quality of service (QoS) in hybrid network. In this paper two simulation scenarios are analyzed for hybrid networks. The nodes in wireless ad hoc networks are mobile in one scenario and static in the other scenario. Both simulation scenarios are used to compare the performance of extended AODV with HCCA (IEEE 802.11e) and without HCCA (IEEE802.11) for real time voice over IP (VoIP) traffic. The extensive set of simulations results show that the performance of extended AODV with HCCA (IEEE 802.11e) improves QoS in hybrid network and it is unaffected whether the nodes in wireless ad hoc networks are mobile or static.展开更多
Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11...Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11 standard series to enhance access medium supporting QoS for multimedia applications. However, some applications such as variable bit rate (VBR) traffic address some challenges in the hybrid coordination function (HCF) nominated to provide QoS. This paper presents a novel priority queuing model to analyze a medium access in the HCF controlled channel access (HCCA) mode. This model makes use of a MAP (Markovian Arrival Process)/PH (Phase Type)/1 queue with two types of jobs which are suitable to support VBR traffic. Using a MAP for traffic arrival process and PH distribution for service process, the inclusion of vacation period makes our analysis very general and comprehensive to support various types of practical traffic streams. The proposed priority queuing model is very useful to evaluate and enhance the performance of the scheduler and the admission controller in the HCCA mechanism.展开更多
This paper addresses the issue of real-time data transmission in vehicles to roadside （V2R） environment by the hybrid coordination function （HCF） of controlled channel access （HCCA） specified by the IEEE 802.1 l...This paper addresses the issue of real-time data transmission in vehicles to roadside （V2R） environment by the hybrid coordination function （HCF） of controlled channel access （HCCA） specified by the IEEE 802.1 lp standard. HCCA is one of the medium access mechanisms in the IEEE 802.11 standard, and uses the polling scheme similar to the point coordination function （PCF） to provide reliable quality of service （QoS）, which may cause resource overshooting and high time consuming. This paper tries to improve the performance of the HCCA polling scheme and designs new data transmission scheduling scheme. The simulation results of the proposal are compared with those of the standard strategy. Simulation results demonstrate that the improved HCCA has lower delay, loss rate, and higher throughput than those of the standard one.展开更多
Hybrid coordination function controlled channel access(HCCA)applied in wireless ad hoc network systems is the strategy to allocate the bandwidth resources of control channel(CCH)and service channels(SCHs).With the con...Hybrid coordination function controlled channel access(HCCA)applied in wireless ad hoc network systems is the strategy to allocate the bandwidth resources of control channel(CCH)and service channels(SCHs).With the continuous development of Internet of vehicles(IoV)technologies,it is difficult for HCCA to support traffic information services,such as low delay along with high-frequency dissemination of security beacons and large capacity interaction of image data.Fusing the fundamental theories of No.7 signaling system and 5G-IoV technologies,this paper proposes a novel channel bandwidth allocation strategy named CO-HCCA,which matches CCH time slot numbers with on board units(OBUs)numbers to reduce the congestion of channel access demand information(CADI);and also illustrates a dynamic segment adjusting algorithm of the time slots.On one hand,in the channel reservation stage of CCH control cycle,OBUs are sorted according to the priority of data transmission,and then the corresponding transmission slots are adopted orderly according to the OBUs numbers,so as to decrease the collision probability of high-frequency dissemination of CADI.On the other hand,for the quickly arriving and leaving OBUs in coverage of roadside base station(RBS),the prediction of bandwidth segments is dynamically adjusted to adapt to the time-varying characteristic of the connected vehicle scenarios.Modeling calculation and objective comparison on OMNeT++computing platform show that the proposed CO-HCCA strategy can effectively reduce the channel congestion of IoV,and in the scenario of high-density data interaction,it is beneficial to promote the transmission timeliness of security beacons and the package delivery rate(PDR)of high bit-rate multiple information.展开更多
文摘基于IEEE802.11e标准,充分考虑混合式协调功能控制信道访问机制(Hybrid Coordination Function Controlled Channel Access,HCCA)的QoS(Quality of Service)参数,提出一个HCCA软件模拟架构;根据此架构,利用NS2网络仿真工具搭建一个功能完整且易于实施的HCCA平台,并结合资源预留方案对平台的有效性和合理性进行仿真验证。
文摘The mobile ad hoc network (MANET) with infrastructure networks (hybrid networks) has several practical uses. The utility of hybrid network is increased in real time applications by providing some suitable quality of service. The quality thresholds are imposed on parameters like end-to-end delay (EED), jitter, packet delivery ratio (PDR) and throughput. This paper utilizes the extended ad hoc on-demand distance vector (AODV) routing protocol for communication between ad hoc network and fixed wired network. This paper also uses the IEEE 802.11e medium access control (MAC) function HCF Controlled Channel Access (HCCA) to support quality of service (QoS) in hybrid network. In this paper two simulation scenarios are analyzed for hybrid networks. The nodes in wireless ad hoc networks are mobile in one scenario and static in the other scenario. Both simulation scenarios are used to compare the performance of extended AODV with HCCA (IEEE 802.11e) and without HCCA (IEEE802.11) for real time voice over IP (VoIP) traffic. The extensive set of simulations results show that the performance of extended AODV with HCCA (IEEE 802.11e) improves QoS in hybrid network and it is unaffected whether the nodes in wireless ad hoc networks are mobile or static.
文摘Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11 standard series to enhance access medium supporting QoS for multimedia applications. However, some applications such as variable bit rate (VBR) traffic address some challenges in the hybrid coordination function (HCF) nominated to provide QoS. This paper presents a novel priority queuing model to analyze a medium access in the HCF controlled channel access (HCCA) mode. This model makes use of a MAP (Markovian Arrival Process)/PH (Phase Type)/1 queue with two types of jobs which are suitable to support VBR traffic. Using a MAP for traffic arrival process and PH distribution for service process, the inclusion of vacation period makes our analysis very general and comprehensive to support various types of practical traffic streams. The proposed priority queuing model is very useful to evaluate and enhance the performance of the scheduler and the admission controller in the HCCA mechanism.
基金supported by the National Natural Science Foundation of China (61072063, NSFC-11-01-01)
文摘This paper addresses the issue of real-time data transmission in vehicles to roadside （V2R） environment by the hybrid coordination function （HCF） of controlled channel access （HCCA） specified by the IEEE 802.1 lp standard. HCCA is one of the medium access mechanisms in the IEEE 802.11 standard, and uses the polling scheme similar to the point coordination function （PCF） to provide reliable quality of service （QoS）, which may cause resource overshooting and high time consuming. This paper tries to improve the performance of the HCCA polling scheme and designs new data transmission scheduling scheme. The simulation results of the proposal are compared with those of the standard strategy. Simulation results demonstrate that the improved HCCA has lower delay, loss rate, and higher throughput than those of the standard one.
基金the National Natural Science Foundation of China under Grant 61573171。
文摘Hybrid coordination function controlled channel access(HCCA)applied in wireless ad hoc network systems is the strategy to allocate the bandwidth resources of control channel(CCH)and service channels(SCHs).With the continuous development of Internet of vehicles(IoV)technologies,it is difficult for HCCA to support traffic information services,such as low delay along with high-frequency dissemination of security beacons and large capacity interaction of image data.Fusing the fundamental theories of No.7 signaling system and 5G-IoV technologies,this paper proposes a novel channel bandwidth allocation strategy named CO-HCCA,which matches CCH time slot numbers with on board units(OBUs)numbers to reduce the congestion of channel access demand information(CADI);and also illustrates a dynamic segment adjusting algorithm of the time slots.On one hand,in the channel reservation stage of CCH control cycle,OBUs are sorted according to the priority of data transmission,and then the corresponding transmission slots are adopted orderly according to the OBUs numbers,so as to decrease the collision probability of high-frequency dissemination of CADI.On the other hand,for the quickly arriving and leaving OBUs in coverage of roadside base station(RBS),the prediction of bandwidth segments is dynamically adjusted to adapt to the time-varying characteristic of the connected vehicle scenarios.Modeling calculation and objective comparison on OMNeT++computing platform show that the proposed CO-HCCA strategy can effectively reduce the channel congestion of IoV,and in the scenario of high-density data interaction,it is beneficial to promote the transmission timeliness of security beacons and the package delivery rate(PDR)of high bit-rate multiple information.
