Performance analysis of a PRMA protocol suitable for voice and datatransmissions in low Earth orbit mobile satellite systems

Mobile satellite systems (MSSs) are expected to play a significant role in providing users with communication services worldwide. In such a context, low Earth orbit (LEO) satellite constellations seem to be a good solution to attain a global coverage and to allow the use of low-power lightweight mobile terminals. This paper analyzes the performance of a novel medium access control (MAC) scheme suitable for applications in LEO-MSSs, named packet reservation multiple access with hindering states (PRMA-HS), that has been derived by proper modifications of the well-known PRMA protocol. We envisage a mixed traffic with voice sources and data sources with different quality of service (QoS) requirements. The good behavior of the proposed PRMA-HS scheme is validated by extensive comparisons with the classical PRMA protocol. Finally, it is shown that PRMA-HS efficiently supports integrated voice and data traffic in LEO-MSSs     

Performance evaluation of a modified PRMA protocol for joint voiceand data packet wireless networks

In this paper, a modified version of the packet reservation multiple-access (PRMA) protocol is proposed to provide spatially dispersed voice and data user terminals wireless access to a base station over a common short-range radio channel. An analytical approach is presented in order to derive system performance in terms of mean data message delay and voice packet dropping probability. A suitable permission probability design is also proposed to enhance system performance. Performance comparisons with an extension of the PRMA protocol to voice data systems previously reported in literature are shown to highlight the better behavior of this approach     

Performance evaluation of an improved PRMA protocol for low earth orbit mobile communication systems

Future mobile communication systems will be characterized by the interworking of several networks that will be integrated into a unique system. The satellite component and the terrestrial one will use as far as possible the same protocols. This work is concerned with Medium Access Control (MAC) protocols. In particular, Packet Reservation Multiple Access (PRMA) has been considered as a good candidate for terrestrial cellular systems, since it allows high multiplexing gains, dynamic PRMA carrier allocation to cells, easy management of integrated voice and data traffic and a near-transparent behaviour with respect to user mobility. The main aim of this preliminary work is to investigate the suitability of the PRMA protocol for application to Low Earth Orbit Mobile Satellite Systems (LEO-MSSs). Moreover, we have proposed a novel version of the PRMA protocol, named PRMA with Hindering States (PRMA-HS), that is particularly suitable for application in LEO systems. This new technique has shown very promising results in terms of both packet dropping probability and throughput. © 1997 John Wiley & Sons, Ltd.     

Voice and data transmissions with a PRMA-like protocol in highpropagation delay cellular systems

Future mobile communication systems will require new medium access control protocols to attain an efficient multiplexing of different traffic sources while guaranteeing their requirements on quality of service. This paper investigates the performance of a modified packet reservation multiple access (PRMA) protocol, called PRMA with hindering states (PRMA-HS), for supporting voice and data transmissions in mobile cellular systems with high propagation delays. A scenario based on low Earth orbit mobile satellite systems (LEO-MSSs) has been considered, but the analytical approach is general. We have obtained that PRMA-HS achieves a high capacity of voice sources in LEO-MSSs also in the presence of data traffic. A performance analysis has been carried out showing good agreement with simulation results. Finally, the PRMA-HS performance has been evaluated in the presence of different data traffic sources     

拥塞控制卫星PRMA-AC协议及性能分析

卫星通信中PRMA协议在负荷较重时由于终端竞争加剧会引起信道拥塞,而较长的传播时延更进一步加剧了拥塞引起的丢包。该文提出一种利用话音终端在通话的不同阶段对信道资源的不同需求对终端进行区分的方案PRMA-AC,据此引入一种接入控制机制,以减少信道竞争,提高系统服务质量。文中给出了系统模型,对协议性能进行了理论分析,获得了新协议下的接入阻塞率、丢包率等性能指标,最后通过仿真与几种卫星通信中常用的PRMA协议进行了对比,证明了协议的性能。     

Performance evaluation of a reservation TDMA protocol for voice/data transmissions in a LEO satellite communication system

In this paper, the capability is investigated of a reservation TDMA‐based protocol to support constant bit rate and best‐effort traffics in Low Earth Orbit (LEO) satellite communication systems under typical propagation conditions. Differently from several previous papers on the same subject, we focus here on a communication channel affected by multipath fading and characterized by a high round trip delay. In our protocol, a higher priority is given to constant bit rate terminals with respect to best‐effort data terminals. The performance for constant bit rate and best‐effort terminals was derived by means of a suitable analytical approach and computer simulations. The results shown herein permits to evaluate the influence of the channel propagation conditions on the system performance. Moreover, they highlight that the reservation TDMA protocol exhibits a good behaviour for the communication channel under consideration and in comparison with a recent protocol based on the classical PRMA scheme. Copyright © 2003 John Wiley & Sons, Ltd.     

C-PRMA: a centralized packet reservation multiple access for localwireless communications

Packet-switched technology has been demonstrated as effective in cellular radio systems with short propagation delay, not only for data, but also for voice transmission. In fact, packet voice can efficiently exploit speech on-off activity to improve bandwidth utilization over time division multiple access (TDMA). Such an approach has been first suggested in the packet reservation multiple-access (PRMA) technique, an adaptation of the reservation ALOHA protocol to the cellular environment. However, being PRMA-based on a fixed frame scheme, it cannot thoroughly take advantage of the very short propagation delays encountered in microcellular systems that allow, for instance, the immediate retransmission of packets lost because of the interference noise from adjacent cells. We present the centralized PRMA, a natural enhancement of PRMA, in which the base station (BS) plays a central role in scheduling the transmissions of mobile stations (MSs). As a consequence, the transmission scheduling is very flexible and can account for the different traffic rate and delay constraints that emerge from voice and data integration. A packet retransmission policy to recover corrupted packets can be implemented and operated efficiently to provide an acceptable grade of service, even in a very noisy environment. The simulation results presented show the quantitative improvements of the centralized packet reservation multiple-access (C-PRMA) performance with respect to PRMA     

Stability and Optimization Analysis for the PRMA Protocol for Voice and Burst Data Integration in a Personal Communication Network

Personal Communication Networks (PCNs) have become an important filed of activity and they are expected to play a fundamental role in next-generation telecommunication systems. In particular, the emerging personal communication services, such as portable computing, paging, personal e-mail, etc. have led to the need of an efficient integration of voice and data traffic in a same PCN by means of a suitable multiple-access scheme. This paper considers stability and optimization issues for the Packet Reservation Multiple Access (PRMA) protocol used for integrating voice and burst data traffic in a PCN. An important result here devised is that the optimized PRMA protocol permits to be achieved good performance even under heavy traffic load conditions.     

A dynamic packet reservation multiple access scheme for wireless ATM

The dynamic packet reservation multiple access (DPRMA) scheme, a medium access control protocol for wireless multimedia applications, is proposed and investigated. DPRMA allows the integration of multiple traffic types through a single access control mechanism that permits users to specify their immediate bandwidth requirements. The primary feature of DPRMA is the dynamic matching of the traffic source generation rates with the assigned portion of the channel capacity. This is accomplished by a control algorithm that regulates the actual amount of channel capacity assigned to users. To support multimedia communication, channel capacity assignments are prioritized by traffic type. The performance of the scheme is evaluated and the scheme is shown to perform well in a system with voice, video conferencing, and data users present. It is also shown to provide improved performance over a system with a modified version of the packet reservation multiple access (PRMA) scheme. Furthermore, several system parameters are studied and optimized.     

Performance evaluation of a reservation TDMA protocol forvoice/data transmission in microcellular systems

This paper deals with a random reservation TDMA protocol able to support constant bit rate services as well as variable bit rate services. In particular, voice communications and data transmissions are considered. Voice terminals have a higher priority assigned than data terminals in accessing the shared channel. A suitable analytical approach is proposed in order to evaluate the data and voice subsystem performance. Comparisons to the well known PRMA scheme are also given in order to highlight the superior performance of the proposed approach in terms of maximum data load and overall throughput     

Performance Analysis of an Enhanced PRMA-HS Protocol for LEO Satellite Communication

The packet reservation multiple access with hindering state （PRMA-HS） is a protocol suitable for LEO satellite mobile communication. Although working well with light system payload （amount of user terminals）, the protocol imposes high channel congestion on system with heavy payload, thus degrades the system＇s quality of service. To controlling the channel congestion, a scheme of enhanced PRMA-HS protocol is proposed, which aims to reduce the collision of voice packets by adopting a mechanism of access control. Through theoretic analysis, the system＇s mathematic model is presented and the packet drop probability of the scheme is deduced. To testify the performance of the scheme, a simulation is performed and the results support our analysis.     

Block Reservation Time Division Multiple Access (BRTDMA) Protocol for a High Capacity Wireless Network

Next generation high capacity wireless networks need to support various types of traffic, including voice, video and data, each of which have different Quality of Service (QoS) requirements for successful transmission. This paper presents an advanced reservation packet access protocol BRTDMA (Block Reservation Time Division Multiple Access) that can accommodate voice and data traffic with equal efficiency in a wireless network. The proposed BRTDMA protocol has been designed to operate in a dynamic fashion by allocating resources according to the QoS criteria of voice and data traffic. Most of the existing reservation protocols offers reservation to voice traffic while data packets are transmitted using contention mode. In this paper we propose a block reservation technique to reserve transmission slots for data traffic for a short duration, which minimizes the speech packet loss and reduce the end-to-end delay for wireless data traffic. The optimum block reservation length for data traffic has been studied in a cellular mobile radio environment using a simulation model. Simulation results show that the BRTDMA protocol offers higher traffic capacity than standard PRMA protocol for integrated voice and data traffic and offers flexibility in accommodating multimedia traffic.     

低轨卫星移动通信系统接入方案

在低轨卫星移动通信系统中,由于卫星和移动用户间的相对运动使得呼叫切换频繁发生.为了降低星间切换请求到达率,减小系统切换开销,本文在距离优先接入方案基础上进一步提出了两种接入策略:覆盖时间优先方案和仰角加权的覆盖时间优先方案.构造了非均匀分布全球话务密度模型.并参照某实际系统参数,对不同接入方案准则下的全球话务服务进行了系统仿真,得到了相应的系统性能参数.     

Packet Reservation Window Multiple Access for Microcellular Voice/Data Transmission

We propose a new packet reservation multiple access (PRMA) scheme for the joint transmission of voice and data traffics in a microcellular medium. The collision resolution protocol within the system is based on a modification of the window random access algorithm, which has superior properties compared to the conventional slotted Aloha. The proposed algorithm, which we call packet reservation window multiple access (PRWMA), works in distinct modes for voice and data without prioritization, and the user performs slightly different operations depending on the information type. Simulation results show that PRWMA outperforms PRMA by a significant margin in terms of voice user capacity.     

Transmit permission control on spread ALOHA packets in LEOsatellite systems

A transmit permission control method for improving the throughput characteristics of a low Earth orbit (LEO) satellite communication system employing spread-slotted ALOHA multiple-access scheme is proposed. Both nonfading and fading satellite links are considered. The basic idea of the proposed scheme is to decrease the level of interference at each satellite and, hence, to increase the probability of packet success, by prohibiting the packet transmission from the users with relatively high propagation loss to their connecting satellites. It is shown that the method has the ability to improve the throughput performance in heavy traffic loads and the peak value of the throughput, significantly. It is also shown that the average delay performance of the system employing the proposed scheme is superior to that of the conventional system at heavy traffic loads     

Protocol for integration of voice and data over frame-based PRMA

A novel protocol for the integration of voice and data over frame based packet reservation multiple access (F-PRMA) is proposed. The voice-priority scheme is employed to provide a quality-of-service (QOS) guarantee for the voice service. Numerical results indicate that a significant amount of data traffic can be supported with a much lower mean packet delay than is achieved with previous protocols, and voice capacity is also improved because it is not necessary to transmit the header message with every packet     

Performance of a joint CDMA/PRMA protocol for mixed voice/datatransmission for third generation mobile communication

A joint code-division multiple-access/packet-reservation multiple-access (CDMA/PRMA) technique is proposed and investigated as a candidate for an uplink protocol for third generation mobile communication systems. Access to the radio channel is controlled such that compared to random access CDMA, interference variance is reduced and throughput increased. Mixed voice/data traffic is investigated for an isolated cell only, whereas voice-only traffic is also investigated in a cellular environment with a regular hexagonal cell structure. Intercell interference is assumed to be Gaussian, and only the average interference level is considered     

CRDA: a collision resolution and dynamic allocation MAC protocol tointegrate data and voice in wireless networks

One key requirement for radio access in advanced, third generation (3G) mobile communication systems is the ability to accommodate a variety of services via a flexible and efficient medium access control (MAC) protocol. The paper presents and evaluates a new multiple access protocol termed CRDA (collision resolution and dynamic allocation), which has the potential to meet the above requirement. CRDA is basically a slotted packet-reservation multiple access technique with dedicated reservation slots, which allows the main shortcoming of previous PRMA schemes, i.e., contention, to be overcome through the integration in the MAC protocol of a code-division multiple-access (CDMA) transmission mode used to access the reservation slots. This prevents collisions during the reservation phase and enhances channel throughput, notably in the case of mixed voice/data traffic. Our simulations of the CRDA MAC integrate voice channels with data sources, generating what we call advanced data traffic, which has a very similar shape to the actual traffic generated by World Wide Web (WWW) applications. The standard assumption of Poissonian data traffic is also considered. Our conclusion is that the CRDA MAC protocol satisfactorily accommodates both types of traffic     

The RRA‐ISA multiple access protocol with and without simple priority schemes for real‐time and data traffic in wireless cellular systems

A multiple access protocol, based on a Reservation Random Access (RRA) scheme, is derived for a wireless cellular network carrying real-time and data traffic. Given a TDMA framed channel and a cellular structure, the aim of the protocol is that of maximizing the one-step throughput over an entire frame. This is achieved by deciding on the access rights at the cell base station, which then broadcasts this information at the beginning of the frame. The decision is made on the basis of binary channel feedback information (collision/no collision) over the previous frames, as well as of long term averages of packet generation rates at the mobile stations, assuming independence in the presence of packets at the latter. The resulting protocol has therefore been termed Independent Stations Algorithm (ISA), and the overall scheme RRA-ISA. As in other RRA protocols, time constrained (e.g., voice) traffic operates in a dynamic reservation mode, by contending for a slot in the frame with the first packet of a burst, and then keeping the eventually accessed slot for the duration of the burst; packets of the time constrained traffic unable to access a slot within a maximum delay are dropped from the input buffer. No such constraint is imposed on data traffic. Together with the “basic” version of the access algorithm, three other variants are presented, which exploit three simple different priority schemes in the RRA-ISA “basic” structure, in order to give a prominence to the voice service. The aim of these variants is to improve the performance in terms of the maximum number of stations acceptable in the system, by slightly increasing the data packets delay. All the proposed schemes are analyzed by simulation in the presence of voice and data traffic. Several comparisons show a relevant performance improvement (in terms of data delay and maximum number of voice stations acceptable within a cell) over other protocols that use ALOHA as a reservation mechanism (RRA-ALOHA or PRMA schemes). This revised version was published online in June 2006 with corrections to the Cover Date.     

Terminal‐Assisted Hybrid MAC Protocol for Differentiated QoS Guarantee in TDMA‐Based Broadband Access Networks

This paper presents a terminal‐assisted frame‐based packet reservation multiple access (TAF‐PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA‐based broadband access networks. In order to achieve a differentiated quality‐of‐service (QoS) guarantee for individual service plus maximal system resource utilization, TAF‐PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame‐by‐frame basis. In addition, we have adopted a terminal‐assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the ‘fair access’ issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF‐PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.