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In W-CDMA (Wideband Code Division Multiple Access)/UMTS (Universal Mobile Telecommunications System), multiuser contention brought by packet scheduling in MAC-layer causes the issue that effectiveness requirements and fairness requirements for TCP in transport-layer are difficult to be guaranteed simultaneously. In order to solve this problem, we propose a novel scheme CL-AACS (active ACK control...
Rate control is an important issue for video streaming in cellular networks. In this paper, we propose an equation based rate control and multiple connections for adaptive video streaming over cellular networks. In our method the sending rate is calculated as a function of round trip time (RTT), loss event rate (p), packet size (s) and new control parameters alpha and beta, that are able to provide...
Today wireless data communication is growing rapidly. In particular, multimedia and Internet communications by wireless systems are the most popular services. Also, the architecture of the wireless networks is varying to support such services better. In this paper, we review, a radio access system, UTRAN (UMTS Terrestrial Radio Access Network), focusing on the RLC (Radio Link Control) and MAC (Medium...
The demand for the wireless Internet requiring broadband is expected to increase in a dramatic way due to popularity of tri player applications including voice, video, and data transmission. The existing wireless technologies UMTS, WiFi, WiMax, may not satisfy the customer requirements, for many reasons including availability, coverage, cost and most importantly mobility. Each technologies has it...
In future mobile networks, different radio access technologies, such as GSM, UMTS, WiMAX, WIFI, will coexist. In order to realize a seamless vertical handover (inter-RAT handover) among these technologies, a variety of interworking architectures and inter-RAT handover mobility managements have been proposed. Based on an integrated coupling architecture, we propose a novel common interworking sublayer...
After acquiring a new Internet protocol (IP) address due to a vertical handover, IP multimedia subsystem (IMS) subscriber has to send session initiation protocol (SIP) messages for registration and session setup to keep an ongoing session. In this paper, we call this registration and session setup delay 'IMS delay.' We show that the IMS delay is unacceptable for supporting real-time applications in...
Session setup time is a critical factor for multimedia applications. Some of the factors that affect the session setup delay are length of SIP messages, bandwidth and packet loss in wireless link This paper aims at reducing the session setup delay in UMTS IP Multimedia Subsystem. We propose compression of SIP header by Text-based Compression using Cache and Blank (TCCB) approach and a caching scheme...
Wireless networks are becoming increasingly popular. These wireless solutions range from personal networks (e.g. Bluetooth), through local (e.g. WiFi) and metropolitan area networks (e.g. WiMax) up to the cellular networks that offer the coverage almost everywhere. As the number of different wireless technologies grows, a unified and standardized mobility support algorithm for heterogeneous networks...
The Radio Link Control (RLC) protocol, used in Universal Mobile Telecommunication System (UMTS) networks, is one of the most advanced and complex link layer protocols. Among its notable features are the absence of retransmission timers, which makes it tolerant to contention for the link, and the ability to abandon persistently lost frames, which makes it suitable for reliable transport layers. In...
A new technique is proposed that enables TCP to distinguish wireless packet losses and spurious timeouts from congestion-related packet losses and timeouts. This is achieved by introducing a wireless enhancement proxy (WENP) that provides radio network feedback to the TCP sender with the aid of two of the TCP header reserved bits. The standard TCP congestion control mechanism is modified to accommodate...
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