Performance Improvements in Heterogeneous Wireless Networks for First   Responders
  Efficient communications are crucial for disaster response and recovery. However, most current public safety land mobile radio (LMR) networks only provide narrowband voice service with limited support of low-speed data services. In this paper, we study to enhance the interoperability of LMR with commercial wireless cellular networks, by which a wide variety of benefits can be offered to disaster responders, including new multimedia services, increased data rates and low cost devices. Our approach is based on Session Initial Protocol (SIP) and a joint radio resource management framework. In addition, an optimal radio resource management scheme is proposed to maximize the overall radio resource utilization and at the same time guarantee service availability and continuity quality of service (QoS) for disaster responders. The effectiveness of the proposed approach is illustrated by numerical examples. 
Jianqiang Zhang
cs.NI