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This paper has evaluated the system performance for the voice over Internet protocol (VoIP) services supported by the IEEE 802.16 systems in terms of the packet loss and delay, and it has also calculated the mean opinion score (MOS) in order to estimate the user's satisfaction for the VoIP services. By the simulation results, the MOS of the VoIP service supported by the unsolicited grant service (UGS)...
This paper presents a Cross-Layer scheme that tries to improve the performance of real-time traffic over TCP in 802.11e wireless networks. It is based on a well-known TCP-friendly, binomial algorithm at the Transport layer, which is jointly configured with the 802.11e protocol at the MAC layer. TCP-friendly schemes have shown to improve the quality of media transfer over wired and wireless networks...
Voice over Internet Protocol (VoIP) is an important service with strict quality-of-service (QoS) requirements in wireless local area networks (WLANs). The popular distributed coordination function (DCF) of IEEE 802.11 medium access control (MAC) protocol adopts a binary exponential back-off (BEB) procedure to reduce the packet collision probability in WLANs. In DCF, the size of contention window is...
This article proposes a solution for two issues in current communications. Firstly, that IMS suffers from client inexistence. Secondly, that mobile operators want to give the subscriber a possibility to access their VoIP network and efficiently cover special areas like airports. To address these problems, we have developed a novel service architecture, which allows 2G subscribers access to a SIP based...
Muni WiFi deployments have been widely covered by the media during the last two years. However, the economical feasibility and performance of such deployments as an alternative for voice services has not been proven. In this paper we measure the voice performance and coverage of the Google network. Then we evaluate the economical feasibility versus cellular deployments. The results show that providing...
In this paper, we present the challenges in supporting multimedia, in particular, VoIP services over multihop wireless networks using commercial IEEE 802.11 MAC DCF hardware, and propose a novel software solution, called Layer 2.5 SoftMAC. Our proposed SoftMAC resides between the IEEE 802.11 MAC layer and the IP layer to coordinate the real-time (RT) multimedia and best-effort (BE) data packet transmission...
In this paper we invent a new architecture for intelligent agent pre-authentication and apply it to seamless handover of VoIP services in integrated WLAN/cellular networks. On the other hand, we incorporate agent-based key distribution into EAP-SIM based AAA protocols for WLAN. Our goal is minimizing the probability of SIP calls blocking resulting from handoff delay. This paper improves the performance...
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