| To an increasing degree in the military communications environment, multiple communi-cation links exist between sending and receiving platforms. This feature increases the communication link reliability as well as possible throughput advantages. However, since each of the channels may not use the same type of devices or transmission methods, the network link characteristics of each link may not be the same. Sometimes, the difference in terms of channel availability and link data rate could be significantly. For example, Navy ships may equip several different types of ship-to-ship radios and satellite backhaul link capabilities. Besides of having differences in channel characteristics among links, there is typically not a coherent approach to utilize these links efficiently. Another exam-ple is an emerging free-space optical and RF dual-communication channel system. In this case, the dynamics of the bandwidth are illustrated since variations from 100’s kbps to more than 10’s Gbps are anticipated. The optical link will be unstable because of line-of-sight (LOS), obstacles, air turbulence, or weather conditions. On the other hand, the RF link would be more stable, but the data rate is comparatively much lower than the optical link. Therefore in both cases, fundamental challenges are needed to address how to dy-namically and seamlessly maintain and control desired levels of Quality of Service (QoS) by using different channels in different links between sender and receiver. Considering the diversity of applications and QoS requirements in military environment, the delivery method for applications via these types of communication links is a challenge. In this pa-per, we propose a Dynamic DiffServ-based Adaptive Queue management scheme (DDAQ) and a data dispatch mechanism to utilize the multilink properties for realizing better QoS support. The DDAQ has the features of some existing queuing methods as well as incorporates a prevailing Diffserv concept. The dispatch function is the control center that dispatches data from queues to links based on pre-defined priorities and chan-nel conditions. A queuing analysis shows benefits of this new mechanism. An OPNET based simulation gives the performance outputs. |
| Dr. Harold Zheng is currently working at Johns Hopkins University Applied Physics Laboratory (APL). Dr. Zheng received his Ph.D. degree in Electrical and Computer Engineering from Georgia Institute of Technology. Before joining APL, Dr. Zheng worked as a researcher in Bell-Labs, Lucent Technologies at Holmdel, NJ, and as a senior consultant in AT&T Labs and Army Research Lab in Ft. Monmouth. He has published a number of papers in wireless QoS, security, 3G wireless networks, and video delivery over wireless and IP networks. |