78 research outputs found

    Handoff effect on PRMA (Packet Reservation Multiple Access) in micro-cellular system

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    PRMA(Packet Reservation Multiple Access) has been proposed for third generation wireless information network by Goodman et al. [5] [4]. Due to small micro cell radius mobile initiated handoff has been proposed to disperse the burden of BS(Base Station) [14]. Even though these frequent handoffs will not burden on BS, increased contends due to handoff will affect the over all performance of PRMA. In this paper, we analyze the handoff effect on PRMA performance under micro-cellular system. Steady state speech terminal model with handoff is proposed.. Stabilities are derived based on proposed steady state terminal model[F(cs)=M] and also increased contend [F(ch)=M] due to handoff. The multiple EPA(equilibrium) points change with handoff. Packet dropping probability and data packet delay are calculated using both Markov Analysis and backlog b from F(cs)=M and F(ch)=M. The changes of performance under handoff show the need of handoff schemes at PRMA

    On the capacity of packet reservation multiple access with capture in personal communication systems

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    In this paper, a new Markovian model is developed to analyze the Packet Reservation Multiple Access (PRMA) protocol over Rician fading channels with lognormal shadowing. The packet dropping probability and the voice user capacity are defined as the performance measures. A new formula is derived to evaluate the dropping probability in the fading environment. The analytical results from our new formula show close agreement with those from computer simulations. The capture effect on the PRMA system performance is also studied. We found that, with capture, the user capacity will be improved and the service quality will degrade gracefully when the number of active users in the system increases. Using the dropping probability as the criterion, we also determine the optimal permission probability in a microcellular environment. © 1996 IEEE.published_or_final_versio

    EQUILIBRIUM ANALYSIS AND CONTROL FOR DESIGN OF PACKET RESERVATION MULTIPLE ACCESS PROTOCOLS

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    The Packet Reservation Multiple Access (PRMA) protocol and its variants have been considered as possible access schemes for communication media for indoor communications, terrestrial communications and satellite communications. Most recently, PRMA (and its variants) has been considered for applications such as beyond third generation and/or fourth generation communication systems, cooperative communication, and multimedia communication in dynamic environments. In this dissertation, equilibrium behavior of general voice and/or data systems employing PRMA are studied along with means for control of this behavior. The main objective is to determine conditions guaranteeing a unique equilibrium for these systems, as multistability can result in an unacceptable user experience. Systems considered include voice systems, voice and data systems, and voice systems with high propagation delay (these are studied both for an error-free channel and a random error channel). Also, various control schemes are introduced and their effect on these system is analyzed at equilibrium. Control schemes considered include a price based control, state estimation-based control, and control using multiple transmission power and capture. For each type of control, the effect of the control on the equilibrium structure of the system is studied, in the spirit of the methodology of bifurcation control. In bifurcation control, the number and nature of steady state solutions of a system are managed by appropriate design of system control laws. Several sufficient conditions for uniqueness of operating points of the PRMA systems under the studied control schemes is determined. Numerical analysis of the equilibrium equations of the systems is provided to support the analytical studies. The equilibrium behavior of voice systems and voice-data systems employing frame-based PRMA is also studied. Effects of price based control on these systems is analyzed. Further, the price based control studied in conjunction with the PRMA systems is extended to a finite buffer finite user slotted ALOHA system, and the equilibrium behavior of the system is studied using a tagged user approach. Among the contributions of the dissertation are analytical sufficient conditions guaranteeing a unique equilibrium point for the various classes of systems studied, control law designs that result in improved system capacity, and extensive numerical studies including comparisons with two previously proposed approaches. Analysis is also given proving the Markovian nature of the system's stochastic dynamics (under some basic assumptions) and the existence of a unique stationary probability law

    Adaptive Control in Wireless Networks

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    Priority-Oriented Adaptive Control With QoS Guarantee for Wireless LANs.

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    In today’s wireless networks there is a great need for QoS, because of the time-bounded voice, audio and video traffic. A new QoS enhanced standard is being standardized by the IEEE 802.11e workgroup. It uses a contention free access mechanism called Hybrid Control Channel Access (HCCA) to guarantee QoS. However, HCCA is not efficient for all types of time-bounded traffic. This work proposes an alternative protocol which could be adapted in HCF (Hybrid Coordination Function). The Priority Oriented Adaptive Control with QoS Guarantee (POAC-QG) is a complete centralized channel access mechanism, it is able to guarantee QoS for all types of multimedia network applications, it enhances the parameterized traffic with priorities, and it supports time division access using slots. Furthermore, it instantly negotiates the quality levels of the traffic streams according to their priorities, supporting multiple streams to the best quality it can achieve. POAC-QG compared to HCCA, provides higher channel utilization, adapts better to the characteristics of the different traffic types, differentiates the traffic streams more efficiently using priorities, and generally exhibits superior performance

    A quantitative comparison of multiple access control protocols for wireless ATM

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    The multiple access control (MAC) problem in a wireless network has intrigued researchers for years. For a broad-band wireless network such as wireless ATM, an effective MAC protocol is very much desired because efficient allocation of channel bandwidth is imperative in accommodating a large user population with satisfactory quality of service. Indeed, MAC protocols for a wireless ATM network in which user traffic requirements are highly heterogeneous (classified into CBR, VBR, and ABR), are even more intricate to design. Considerable research efforts expended in tackling the problem have resulted in a myriad of MAC protocols. While each protocol is individually shown to be effective by the respective designers, it is unclear how these different protocols compare against each other on a unified basis. In this paper, we quantitatively compare seven recently proposed TDMA-based MAC protocols for integrated wireless data and voice services. We first propose a taxonomy of TDMA-based protocols, from which we carefully select seven protocols, namely SCAMA, DTDMA/VR, DTDMA/PR, DQRUMA, DPRMA, DSA++, and PRMA/DA, such that they are devised based on rather orthogonal design philosophies. The objective of our comparison is to highlight the merits and demerits of different protocol designs.published_or_final_versio

    Performance analysis of CAR: Centralized adaptive reservation

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    A centralized adaptive reservation (CAR) protocol has been proposed in [1] for supporting constant bit rate (CBR), variable bit rate (VBR) and unspecified bit rate (UBR) services in a starconfigured network. This protocol has two main features. First, both the access probability and the bandwidth for reservation requests are varied dynamically to enhance efficiency. Second, by using a request-mini-slot method, UBR traffic can only utilize the residual bandwidth of the other traffic. In this paper, we derive a Markov chain model for analyzing the performance of the CAR protocol by means of a bi-state traffic source. The focus is to analyze the performance of the VBR stations when both the access probability and the bandwidth for reservation requests are changed dynamically.published_or_final_versio

    A MAC protocol for IP-based CDMA wireless networks.

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    Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.The evolution of the intemet protocol (IP) to offer quality of service (QoS) makes it a suitable core network protocol for next generation networks (NGN). The QoS features incorporated to IP will enable future lP-based wireless networks to meet QoS requirements of various multimedia traffic. The Differentiated Service (Diffserv) Architecture is a promising QoS technology due to its scalability which arises from traffic flow aggregates. For this reason, in this dissertation a network infrastructure based on DiffServ is assumed. This architecture provides assured service (AS) and premium service (PrS) classes in addition to best-effort service (BE). The medium access control (MAC) protocol is one of the important design issues in wireless networks. In a wireless network carrying multimedia traffic, the MAC protocol is required to provide simultaneous support for a wide variety of traffic types, support traffic with delay and jitter bounds, and assign bandwidth in an efficient and fair manner among traffic classes. Several MAC protocols capable of supporting multimedia services have been proposed in the literature, the majority of which were designed for wireless A1M (Asynchronous Transfer Mode). The focus of this dissertation is on time division multiple access and code division multiple access (TDMAlCDMA) based MAC protocols that support QoS in lP-based wireless networks. This dissertation begins by giving a survey of wireless MAC protocols. The survey considers MAC protocols for centralised wireless networks and classifies them according to their multiple access technology and as well as their method of resource sharing. A novel TDMAlCDMA based MAC protocol incorporating techniques from existing protocols is then proposed. To provide the above-mentioned services, the bandwidth is partitioned amongst AS and PrS classes. The BE class utilizes the remaining bandwidth from the two classes because it does not have QoS requirements. The protocol employs a demand assignment (DA) scheme to support traffic from PrS and AS classes. BE traffic is supported by a random reservation access scheme with dual multiple access interference (MAl) admission thresholds. The performance of the protocol, i.e. the AS or PrS call blocking probability, and BE throughput are evaluated through Markov analytical models and Monte-Carlo simulations. Furthermore, the protocol is modified and incorporated into IEEE 802.16 broadband wireless access (BWA) network
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