Multiple slot allocation for voice/data transmission over PRMA++ applied to FRAMES multiple access mode 1

This paper presents some simulation results of PRMA++ for voice and data transmission over a physical air interface platform defined in the ACTS European project FRAMES. Variations on the statistics of speech sources (activity factor, petition rate) are studied and conclusions are obtained for optimal frame dimensioning. For data transmission, a multiple slot allocation scheme is presented and results are shown for different source rates and packet lengths.Peer ReviewedPostprint (published version

A quantitative comparison of multiple access control protocols for wireless ATM

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

The Feasibility of ATM operations over high frequency radio and the viability of the ATM/HF architecture

High Frequency (HF) radio is still a vital part of communications networks because its low cost and long distance capabilities, and still plays important roles as primary, supplemental, or redundant backup systems. Asynchronous Transfer Mode (ATM) is increasingly becoming an important part of communications, especially with LAN Emulation (LANE) specifications. Add to this the importance and increasing interest and dependency upon wireless networking, and it becomes inevitable that research into mobile ATM networking over HF radio would be considered. To test the feasibility of ATM networking over HF radio it was decided that a simulation would be developed to collect some basic information on call blocking and throughput. In order to build the simulation it was necessary to have an architectural framework of a mobile ATM network operating over HF radio. ATM/HF (ATM over HF) is the proposed architecture. ATM/HF is a proposed architecture that provides for networking mobile ATM nodes such as ships, planes, and trucks, over HF radio. It is based upon a recommended 64 kHz bandwidth which allows for a 128 kbps data rate. The ATM/HF architecture utilizes three different Media Access Control (MAC) protocols for network startup and access from the various network states, and incorporates several recently proposed dynamic capabilities for control of bandwidth and the integration of voice, data, and video. The proposal provides frame and wireless ATM (WATM) packet structures and a reference model for flow of the cells from the ATM Adaptation Layer (AAL) through the radio. An important feature is the use of channels, called channelization, to increase both network capacity and distance. The simulation was built to represent an active network state with active nodes connecting and disconnecting calls in a dynamic way with explicit connection messages. The purpose of starting from this network state was to measure the call blocking and throughput of a single channel. Two user types were developed, one to represent telephone voice and the other to represent computer data traffic. By varying the number of users per node and by type, the level of call blocking and throughput could be changed. Graphing the levels it could be determined the maximum capacity a single channel could support and thus determine if ATM over HF radio is feasible. In addition, the same information was used to determine the viability of the ATM/HF architecture. Although the simulation did not incorporate all the dynamic features of the recommended protocols, it does dynamically assign slots, rearrange slots to utilize non-contiguous available slots, and adjust the data rate of computer connections to accommodate voice call requests. This was done to reduce the level of voice call blocking which became the determining factor in deciding feasibility. It was determined that mobile ATM networking over HF radio is possible since the voice call blocking of a single channel was at the 10% level, overall call blocking was at the 6% level, and throughput was at the 53% level. It was determined that a single channel could support six voice and a minimum of ten data users. Although throughput, which is defined as the number of available slot used, was lower than expected, the possibility exists for utilizing the unused slots by incorporating additional dynamic capabilities that would increase the number of users supportable by a single channel. Throughput can be also be increased by incorporating Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) traffic. The call blocking and throughput levels prove that ATM/HF is a viable method for supporting ATM operations. Although the call blocking level achieved the voice call blocking level and exceeding the overall call blocking level, the throughput level shows that there is a lot of wasted bandwidth. Further study of the design is required to improve the throughput level. Further development of the simulation is required in order to test the MAC protocols and to test the effects of the Bit Error Rate and fading effects of HF radio. The final conclusion, however, is that ATM over HF radio is feasible, that ATM/HF is a viable architecture, and that further research should be conducted into both

A flexible medium access control framework for multimedia application support in wireless ATM

Includes bibliographical references.The field of wireless communications has seen phenomenal development over the last decade. With the current abundance of applications that use broadband multimedia over wired networks it is logical that users will want to have access to these same multimedia streams [rom a mobile terminal. Wireless solutions for connectivity to networks such as Ethernet networks already exist, however, a method of supporting access to an ATM network from a mobile terminal has not yet been standardised. Transporting ATM data over the wireless medium poses a number of problems. The Medium Access Control (MAC) layer of any proposed wireless ATM network would be responsible for resolving many of these problems. Unfortunately, research into MAC layers is hampered by the fact that most existing MAC layers cannot be modified in order to experiment with the effectiveness of the many MAC protocol techniques that exist

A MAC protocol for IP-based CDMA wireless networks.

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

A slotted-CDMA based wireless-ATM link layer : guaranteeing QoS over a wireless link.

Thesis (M.Sc.)-University of Natal, Durban, 2000.Future wireless networks will have to handle varying combinations of multimedia traffic that present the network with numerous quality of service (QoS) requirements. The continuously growing demand for mobile phones has resulted in radio spectrum becoming a precious resource that cannot be wasted. The current second-generation mobile networks are designed for voice communication and, even with the enhancements being implemented to accommodate data, they cannot efficiently handle the multimedia traffic demands that will be introduced in the near future. This thesis begins with a survey of existing wireless ATM (WATM) protocols, followed by an examination of some medium access control (MAC) protocols, supporting multimedia traffic, and based on code division multiple access (CDMA) physical layers. A WATM link layer protocol based on a CDMA physical layer, and incorporating techniques from some of the surveyed protocols, is then proposed. The MAC protocol supports a wide range of service requirements by utilising a flexible scheduling algorithm that takes advantage of the graceful degradation of CDMA with increasing user interference to schedule cells for transmission according to their maximum bit error rate (BER) requirements. The data link control (DLC) accommodates the various traffic types by allowing virtual channels (VCs) to make use of forward error correction (FEc) or retransmission techniques. The proposed link layer protocol has been implemented on a Blue Wave Systems DSP board that forms part of Alcatel Altech Telecoms' software radio platform. The details and practicality of the implementation are presented. A simulation model for the protocol has been developed using MIL3 's Opnet Modeler. Hence, both simulated and measured performance results are presented before the thesis concludes with suggestions for improvements and future work

A novel channel-adaptive uplink access control protocol for nomadic computing

We consider the uplink access control problem in a mobile nomadic computing system, which is based on a cellular phone network in that a user can use the mobile device to transmit voice or file data. This resource management problem is important because an efficient solution to uplink access control is critical for supporting a large user population with a reasonable level of quality of service (QoS). While there are a number of recently proposed protocols for uplink access control, these protocols possess a common drawback in that they do not adapt well to the burst error properties, which are inevitable in using wireless communication channels. In this paper, we propose a novel TDMA-based uplink access protocol, which employs a channel state dependent allocation strategy. Our protocol is motivated by two observations: 1) when channel state is bad, the throughput is low due to the large amount of FEC (forward error correction) or excessive ARQ (automatic repeated request) that is needed and 2) because of item 1, much of the mobile device's energy is wasted. The proposed protocol works closely with the underlying physical layer in that, through observing the channel state information (CSI) of each mobile device, the MAC protocol first segregates a set of users with good CSI from requests gathered in the request contention phase of an uplink frame. The protocol then judiciously allocates channel bandwidth to contending users based on their channel conditions. Simulation results indicate that the proposed protocol considerably outperforms five state-of-the-art protocols in terms of packet loss, delay, and throughput.published_or_final_versio