基于QoS升降级的无线异构网动态带宽分配策略研究

Study of a dynamic bandwidth assignment strategy based on QoS upgrade/degradation for heterogeneous wireless networks

利用异构无线网络环境下实时多媒体业务传输带宽可变的特点,提出一种基于服务质量(QoS)升降级的动态带宽分配策略。该策略针对系统带宽资源不足的情况,给出基于信道容量对多媒体用户进行平缓QoS升降级的方法,使系统在用户可接受的降级程度内接入更多的呼叫,进一步,为得到满意的服务等级(GoS),设置一个限制新呼叫接入的带宽阈值,并基于Markov模型给出该阈值的计算方法。与固定划分降质水平的带宽分配策略比较的结果表明,上述带宽分配策略能有效降低新呼叫阻塞率(CBP)与切换呼叫中断率(HDP),同时能明显提高带宽资源利用率。

Considering the feature that the bandwidth for real-time multimedia traffics in heterogeneous wireless networks is alterable, the paper proposes a dynamic bandwidth assignment strategy based on upgrading or downgrading the level of quality of service （QoS）. When a network system has no sufficient bandwidth resources, the strategy gives a method for smoothly upgrading or downgrading the QoS level of multimedia users based on the channel capacity to set free some bandwidth from the users for more new calls and handoff calls while the users＇ traffics are still at an acceptable level. Farther, a bandwidth threshold to limit new calls for a satisfied grade of service （GoS） is defined, and the algorithm for the threshold is introduced based on the Markov model. By comparison with the fixed QoS degradation strategy, this strategy can lower the call blocking probability （CBP） and the handoff dropping probability （HDP） effectively, and can improve the bandwidth utility markedly.