Selecting transparently a proper network connection for voice communication will be a fundamental requirement in future multi-mode heterogeneous wireless network. This paper presented a smart session selection (S3) scheme to meet this requirement. Instead of selecting a best access network as in conventional Always Best Connected (ABC) paradigm, S3 enables users to select a best network connection, which consists of source and destination access network pair, to satisfy quality constraint and users' preference. To support S3, we develop a user profile to specify network connection priority. Meanwhile IP multimedia subsystem (IMS) is extended to make smart decision for users. Finally, Analytic Hierarchy Process (AHP) is used to recommend a network connection with assistance of user profile and IMS signaling. An example is illustrated to show that AHP can successfully select a good network connection that fulfills the requirement of users.

QMNF is a QoS-aware multicast routing protocol using N-hop dominating flooding and built upon a layered routing architecture. In this architecture, QMNF invites the N-hop flooding component and the shortest path routing table from OSPF by open signaling interfaces, floods the path-probing packets, and employs a two-pass resource reservation scheme to avoid unnecessary resource reservation. The QMNF is QoS-aware, loop-free, flexible and scalable, and improves network resource utilization. In our simulation, the performance of QMNF is compared with that of traditional flooding protocol with the shortest path resources reservation, a traditional flooding protocol with the widest path resources reservation, PIM and QMBF. The simulation results confirm that QMNF has a high success rate and good resource utilization, and it can distribute traffic in a network evenly.

This paper proposes a cross layer wireless VoIP service which integrates an Adaptive QoS Playout (AQP) algorithm, E-model, Stream Control Transmission Protocol (SCTP), IEEE 802.21 Media Independent Handover (MIH) middleware and two user motion detection services. The proposed AQP algorithm integrates the effect of playout control and lost packet retransmission based on the E-model. Besides, by using the partial reliable transmission service from SCTP and the handoff notification from MIH services in a cross layer manner, AQP can reduce the lateness loss rate and improve speech quality under high frame error rates. In the simulations, the performance of AQP is compared with a fixed playout algorithm and four adaptive playout strategies. The simulation results show that the lateness loss rate of AQP is 2% lower than that of existing playout algorithms and the R-factor is 16% higher than the compared algorithms when a network has 50 ms wired propagation delay and 2.5% frame error rate.