A unified performance model for reservation-type multiple-access schemes

This paper presents a unified performance model for the integrated voice/data wireless system using reservationtype multiple-access (MA) schemes. It is observed that although these schemes are different in the frame structure and resource assignment procedure, all of them can be described by several common state variables whose evolvement exhibits the Markovian property. Based on this observation, a general Markovian model is developed in this paper. Three performance measures, namely, voice-packet-loss probability, data throughput, and data delay are defined. As a special case, the performance evaluation model for the voice-only system is also presented. Numerical results are given and verified by simulation under both voice-only and integrated scenarios using packet-reservation MA (PRMA), dynamic time-division multiple access (D-TDMA), and resourceauction multiple access (RAMA) as examples. It is found that our analytical model is quite accurate, especially in the region of interest. The impact of system parameters (such as the voice-permission probability, data-retransmission probability, maximum number of voice slots per frame, etc.) on the integrated system performance is also investigated for these three example systems. © 1998 IEEE.published_or_final_versio

Adaptive S-ALOHA CDMA as an alternative way of integrating services in mobile environments

Code-division multiple-access (CDMA) schemes appear to be very promising access techniques for coping with the requirements of third-generation mobile systems, mainly because of their flexibility. This paper proposes an adaptive S-ALOHA DS-CDMA access scheme as a method for integrating nonreal-time (i.e., Internet applications) and real-time (i.e., voice) services in a multicell scenario by exploiting the potentials of CDMA under time-varying channel load conditions. The adaptive component makes data terminals autonomously change their transmission rate according to the total (voice+data) channel occupancy, so that the minimum possible data delay, which can be analytically obtained by defining a birth-death process, is almost always achieved. Moreover, by means of a simplified cellular model, the proposed algorithm revealed the same behavior, i.e., it tries to select the most suitable transmission rate at any time slot, when it is affected by intercell interference and even by power control imperfections. Finally, in order to gain more insight into the potentials of such an access strategy, the adaptive S-ALOHA CDMA scheme is then compared to a reservation time-division multiple-access (TDMA)-based protocol (PRMA++), showing the benefits of the CDMA-based solution in terms of capacity, flexibility, and data delay performance.Peer Reviewe

Performance Studies of Multimedia Traffic in CDMA Cellular Network

The current generation of wireless cellular network is mostly used for voice communication. Although data services such as short message services (SMS) are available, voice communication still takes precedence. However, in the near future, it is anticipated that wireless communication is expected to handle multimedia traffic that is currently available on land networks. Multimedia traffic includes video services such as real time video and audio, voice services and data services similar to the ones available in the Internet. The cellular network carrying multimedia traffic is analysed in a single cell where Code Division Multiple Access (CDMA) protocol is used for users to access the network simultaneously. The study is analysed for the reverse link communication, i. e., communication between the user and the base station. CDMA is used because of its merits in minimising the effect of interference, increasing cell capacity and high security features compared to other access technologies. The model inputs include co- channel interference, signal to noise ratio, bit error rate requirements, number of users, the channel access priority and threshold. Suitable assumptions to enable simulation are made. The model is simulated to see the impact of complementing data traffic along with voice and video traffic. The model is also simulated for synchronous transmission and asynchronous transmission of packets. The results shows that data traffic can be successfully complemented along with voice and video traffic without significantly degrading voice and video delay. Data traffic can tolerate delay but is loss sensitive. Data traffic delay can be used without suffering any loss, even by reducing the data access priority. The model also compared the effects of synchronous and asynchronous transmission. Synchronous transmission indicated an overhead in packet delay compared to asynchronous transmission. It is concluded from the work that voice, video and data traffic can be served in a cell simultaneously with asynchronous transmission. A higher bandwidth can assure a higher number of multimedia users in a asynchronous CDMA cellular network. The model will serve as a useful design tool

Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

A Performance Analysis of a Joint LMDS/ Satellite Communication Network

The goal of this research is to provide a performance analysis of a joint terrestrial/ satellite communication network. The systems of interest are the Local Multipoint Distribution Service (LMDS) terrestrial system and the proposed Teledesic satellite network. This analysis is performed using the OPNET network simulation tool. Simulations are run for twelve separate scenarios involving three factors which include: number of users, modulation type, and Quality of Service (QoS). The key metrics for characterizing simulation scenarios are the end-to-end delay, bit error rate, and average system throughput. The results obtained display the benefit of improved throughput, approximately 20 Mbps for the low user load and approximately 8 to 11 Mbps for the high user load, when the modulation schemes where changed. This improvement comes at the expense the bit error rate. For example, the bit error rate increased by a factor of 5 for the low user load when changing from BPSK to QPSK and by a factor of 1.5 for the QPSK to 8-PSK change. The peak end-to-end delay results, ranging from .053 seconds to .446 seconds, proved to support real-time voice communication for all but one scenario (BPSK/ high user load). The QoS proved to be a benefit for scenarios with a high user load (150 users) increasing the average throughput by 2 to 4 Mbps. The QoS also reduced the peak end-to-end delay, narrowing the range from .04 to .104 seconds. The analysis of these three main operational characteristics gives a fundamental look at the joint network\u27s performance capabilities

HWN* Mobility Management Considering QoS, Optimisation and Cross Layer Issues

In this paper, we address mobility management for 4th generation heterogeneous networks from a quality of service (QoS), optimisation and cross layer design perspective. Users are classified as high profile, normal profile and low profile according to their differentiated service requirements. Congestion avoidance control and adaptive handover mechanisms are implemented for efficient cooperation within the mobile heterogeneous network environment consisting of a TDMA network, ad hoc network and relay nodes. A previous proposed routing algorithm is also revised to include mobility management

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

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

Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications