A Hybrid Adaptive Wireless Channel Access Protocol for Multimedia Personal Communication Systems

This paper proposes a new medium access protocol (MAC) protocol for futurewireless multimedia personal communication systems, denoted hybrid andadaptive multiple access control (HAMAC) protocol. The HAMAC protocolintegrates fixed assignment TDMA protocol, reservation-based protocols, andcontention-based protocols into a single wireless network so as tosimultaneously and efficiently support various classes of traffic such asconstant-bit-rate (CBR), variable-bit-rate (VBR), and available-bit-rate (ABR)traffic. In particular, the HAMAC protocol uses a novel preservationslot technique to overcome the packet contention overhead in packetreservation multiple access (PRMA) like protocols, while keeping mostisochronous service features of TDMA protocols to serve voice and CBR trafficstreams. A preservation slot is a very short slot which is used torepresent a CBR connection when the traffic in the CBR connection is in asilent period in which there is no meaningful data to transmit. Due to thevery short length of the preservation slot, it only takes minimalportion of the bandwidth pre-allocated to the CBR connection, so that theremaining bandwidth can be freed for other connections to use. When the CBRsource becomes active again, the preservation slot is replaced bynormal data slots without any reservation operation, extra delay, orsignificant bandwidth loss. Consequently, the guaranteed service andsimplified signaling features of TDMA protocols, together with the adaptivebandwidth allocation features of PRMA-like protocols, are both realized in theHAMAC protocol. We have analyzed the performance of the HAMAC protocol usingextensive simulations. The results show that the HAMAC protocol can achievevery low loss rates for various multimedia traffic with stringent quality ofservice (QoS) requirements and outperforms state-of-the-art PRMA-likeprotocols. As a result, the HAMAC protocol appears to be a good candidate forfuture generation multimedia personal communication systems.     

卫星通信系统中的多址接入协议

简述了卫星通信中多址协议的分类和影响多址协议性能的因素,重点介绍了三种预约多址协议PRMA-HS、PRMA/CDMA和Butst Reservation CDMA,并分析了它们的性能.     

BGP-S: A Protocol for Terrestrial and Satellite Network Integration in Network Layer

To accomplish network layer integration of terrestrial and satellite IP networks, special exterior gateway protocols are needed. In this work, a new exterior gateway protocol called Border Gateway Protocol – Satellite version (BGP-S) is introduced that enables automated discovery of paths that go through the satellite network. This protocol is designed to work in only one terrestrial gateway in every Autonomous System and enables the forwarding of discovered paths in the Internet using the BGP-4 protocol. The performance of BGP-S is investigated through simulations.     

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     

Stability analysis of an adaptive packet access scheme for mobile communication systems with high propagation delays

In this paper, we investigate a packet access scheme that is able to support mixed traffics in the presence of high propagation delays. Referring to a Time‐Code Division Multiple Access air interface, we propose a Medium Access Control (MAC) protocol based on a random access scheme. A successful attempt grants the use of a slot‐code resource. This protocol is named Adaptive Time Code‐Packet Reservation Multiple Access (ATC‐PRMA), since the access parameters are changed, depending on the traffic load conditions, so as to fulfil Quality of Service requirements. Numerical examples are carried out for the Low Earth Orbit (LEO)‐Mobile Satellite System (MSS) scenario, but all these considerations could be applied to High‐Altitude Platform Stations (HAPSs) as well. In both cases, high propagation delays prevent an immediate feedback to users. An analytical approach is proposed to study the stability of our MAC scheme. Accordingly, we define a criterion for optimizing system performance. The predicted ATC‐PRMA behaviour is supported by simulation results. Finally, we show the performance improvement of ATC‐PRMA with respect to a MAC protocol not employing adaptive parameters. Copyright © 2003 John Wiley & Sons, Ltd.     

Performance of an exponential backoff scheme for slotted-ALOHAprotocol in local wireless environment

Slotted ALOHA is widely used in local wireless communications not only by itself as a multiple access protocol but also as a component in many reservation protocols. The paper suggests a very simple backoff scheme for slotted ALOHA and evaluates its performance in local wireless environments. The authors analyze the system capacity in full load conditions and the throughput-delay characteristics in underload conditions. They conduct a computer simulation to evaluate the system performance in transient-state. They also give a protocol parameter value which is highly recommendable from the practical viewpoint. As an application example, they examine the packet reservation multiple access (PRMA) system with the suggested backoff scheme and compare its performance with that of the original PRMA system     

Protocol architectures for satellite ATM broadband networks

The latest developments and experimentation in asynchronous transfer mode (ATM) technology show that ATM will be a candidate transport mechanism in many private and public multimedia networks. Furthermore, the interest in satellite ATM systems has grown considerably because they can rapidly and economically extend the boundaries of any terrestrial network. Currently, there is a huge increase in the demand for satellite communications operating at the Ka-frequency bands; several different systems have been proposed and are under development worldwide. Two main scenarios for satellite access network protocols are presented in this article. The first one uses ATM cell encapsulation and satellite-specific protocols for establishing and managing a connection, whereas the second one provides a highly integrated solution with the ATM protocol stack and defines a new satellite ATM (S-ATM) protocol layer     

A contention/reservation access protocol for speech and data integration in TDMA‐based advanced mobile systems

The performance of third generation mobile systems is greatly influenced by the multiple access protocols used in the radio access system. The paper introduces a multiple access protocol, SIR (Service Integration for Radio access), which has the potential for accommodating the requirements of speech and bursty data traffic in an efficient way. SIR is evolved from an access protocol (PRMA++) studied within the framework of the TDMA-based version of the European evolving standard for third generation mobile systems. In particular, SIR uses the same frame structure and in-band signalling but introduces a contention-free handling of data bandwidth requests while meeting speech service requirements via basic PRMA++ mechanisms. This revised version was published online in June 2006 with corrections to the Cover Date.     

Analysis of an integrated voice and data transmission system usingpacket reservation multiple access

Packet reservation multiple access (PRMA) is a channel access protocol proposed for the third generation wireless information networks which have attracted considerable attentions recently. By using the equilibrium point analysis (EPA), a PRMA integrated voice and data system has been studied in previous research. However, the error between numerical results of the analysis and those of simulation is relatively large. In this paper, we also study an integrated voice and data system with PRMA. The system performance is evaluated by using a Markov analysis method. First, some analytic models are constructed such that the system transition can be described by a Markov chain. Then, we calculate the entries of the one step state transition matrix using an iterative procedure. Finally, system performance measures, such as throughput and delay, are evaluated. Little error between numerical results of analysis and those of simulation indicates that the method is appropriate to analyze PRMA systems,     

Contention-TDMA protocol: performance evaluation

A hybrid access protocol known, as contention time-division multiple access (C-TDMA), is presented and analyzed in a radio cellular multiuser system scenario. C-TDMA shows some features of contention-based (slotted-ALOHA) and reservation-based (packet reservation multiple access, PRMA) protocols. It has been recommended for use in the uplink of future European multimedia distribution systems. A simple Markov model is proposed to describe C-TDMA behavior. A complete statistical analysis of the model has been made in order to evaluate the performance of the protocol. However, due to the long computation time required in the presence of a large number of users, a simpler approach known as equilibrium point analysis (EPA) is used. Moreover, on the basis of the EPA analysis and the C-TDMA design parameters, a fast algorithm has been developed to improve the achievable throughput of C-TDMA. Results in terms of throughput and delay under variable traffic conditions indicate that C-TDMA is able to grant optimum throughput/delay figures for typical multiuser systems. Moreover, for a digital speech scenario, a performance comparison with PRMA demonstrates that C-TDMA yields equivalent performance to PRMA in terms of number of users supported by the system with a limited packet dropping rate     

Control of the Interworking Between Packet Reservation Multiple Access and Dynamic Carrier Allocation

This work deals with an enhanced frequency division multiplex/packet reservation multiple access (FDM/PRMA) technique for cellular systems also suitable for wireless local area networks (WLANs); such enhancements consist of an efficient control of the interworking between dynamic carrier allocation (DCA) strategies, which guarantee a real-time rearrangement of the carriers-to-cells assignment and PRMA techniques. This allows a higher carrier exploitation. In this respect, the novelties introduced in this paper are: (i) the definition of a short-term packet dropping probability which permits the real-time assessment of the link quality of a PRMA carrier; (ii) the determination of a procedure the base station (BS) can follow in order to perform a real-time estimation of the above-mentioned short-term parameter; (iii) an efficient carrier management and interworking between the DCA mechanism and the PRMA technique realized by means of such parameter. The paper also shows simulation results highlighting a remarkable improvement of the carrier utilization, obtained by the proposed interworking of the DCA and PRMA techniques.     

Dynamic Reservation Multiple Access (DRMA): A new multiple access scheme for Personal Communication System (PCS)

To improve the spectrum efficiency of integrated voice and data services in Personal Communication System (PCS), several reservation-type multiple access schemes, such as Packet Reservation Multiple Access (PRMA), Dynamic Time Division Multiple Access (D-TDMA), Resource Auction Multiple Access (RAMA), etc., have been proposed. PRMA uses the data packet itself to make a channel reservation, and is inefficient in that each unsuccessful reservation wastes one slot. However, it does not have a fixed reservation overhead and offers shorter access delay. On the other hand, fixed reservation overhead is unavoidable in both RAMA and D-TDMA. Compared to D-TDMA and PRMA, RAMA is superior in the sense that its slot assignment is independent of the traffic load. But its implementation is difficult. With these observations, a new reservation protocol, called Dynamic Reservation Multiple Access (DRMA), is proposed in this paper. With this new protocol, the success probability of channel access is greatly improved at the expense of slightly increased system complexity. It solves the problem of inefficiency in PRMA, but without introducing the fixed reservation overhead as in D-TDMA and RAMA. In addition, it is more suited to the dynamic behavior of the integrated traffic because there is no fixed boundary between voice and data slots (which is mandatory in D-TDMA and RAMA). Our numerical results indicate that its performance is superior to the existing reservation protocols, especially in the integrated traffic scenario. Moreover, the soft capacity feature is exhibited when the traffic load increases.     

Proposal and performance evaluation of an efficient multiple-access protocol for LEO satellite packet networks

This paper deals with a modified version of the packet reservation multiple-access (PRMA) protocol suitable for integration of real-time (voice) and best effort (data) traffic in low Earth orbit (LEO) satellite communication systems. The proposed scheme differs from previous alternatives on the method adopted to handle access requests for voice and data terminals, and to transmit data messages. An analytical approach is proposed and validated in the case of voice and classical (i.e., geometric distributed) data traffic in order to derive system performance in terms of mean data message delay and voice packet dropping probability. However, in order to better highlight the advantages of the proposed approach typical interactive and background traffics types have been also considered. Performance comparisons with previous proposed PRMA protocols for voice and data transmission in LEO satellite communication systems are also shown in order to highlight the better behavior of the proposed scheme. Finally, a brief discussion concerning the extension of the proposed S-PRMA protocol to the case of different satellite communication systems is also provided.     

PRMA performance in cellular environments with self-adaptivechannel allocation strategies

The personal communication systems envisaged for next years will have to accommodate a wide range of services with different quality requirements (on delays, bit error rates, etc.), and will often be characterized by a high burstiness (i.e., with relatively short traffic bursts, alternating with comparatively long silence periods). Therefore, an extension of packet communications to the cellular scenario is appealing for its inherent flexibility. The packet reservation multiple access (PRMA) protocol is considered. On the other hand, the current trend in reducing cell sizes poses major planning problems, which cannot be properly coped with by the usual fixed channel allocation methods; therefore, adaptive allocation schemes, which are able to avoid any frequency planning, are currently studied. A review of adaptive channel allocation strategies in view of application to packet switching is carried out. Then, a self-adaptive assignment method (channel segregation) originally developed for circuit switched systems is selected and conveniently adapted for PRMA operations. Simulations show good performance, provided that values of some system variables are correctly chosen     

Performance of CDMA/PRMA as an Access Technique for Integrated Services in a UMTS High Altitude Platform System

High Altitude Platforms (HAPs) have gained a great interest in recent years. HAP systems will be global in nature but national in service provision. They will deliver IMT-2000 mobile and fixed wireless access using the proposed IMT-2000 terrestrial component radio transmission technologies and protocols. Under the above consideration, in this paper the performance of a MAC protocol based on the combination of the well-known Packet Reservation Multiple Access (PRMA) scheme with Code Division Multiple Access (CDMA) technologies in a Frequency Division Duplex (FDD) mode is studied, for a HAP operating at the 2 GHz frequency band at an altitude of 22 km. The impact of acknowledgement delay has been examined through computer simulations, along with the selection of suitable channel access functions (CAFs) to control the access of mobile users. Moreover the protocol performance is investigated in a cellular HAP environment and compared to that of a ground-based system. Finally, different traffic scenarios have been considered in order to investigate the access delay for non-real time traffic and the packet dropping performance for real time traffic.Nikolaos Batsios received his diploma degree in electrical & computer engineering (Telecommunication Division) from Aristotle University of Thessaloniki (Greece) in 2000. At the end of his studies, his diploma thesis was awarded from ERICSSON Hellas. He was also one of the six finalists of the IEEE Region 8 Student Paper Contest. He has worked as a Research Engineer in Space Engineering S.p.A. (Rome, Italy) and he was involved in ATB, ROBMOD and VIRTUOUS projects. Currently he is working in Intracom S.A. as Telecom Engineer. His research interests are in the field of satellite and terrestrial communication systems including physical layer design, medium access control layer architectures and protocols.Fotini-Niovi Pavlidou received the PhD degree in electrical engineering from the Aristotle University of Thessaloniki, Greece, in 1988 and the diploma in mechanical-electrical engineering in 1979 from the same institution. She is currently an associate professor at the Department of Electrical and Computer Engineering at the Aristotle University engaged in teaching for the under- and post-graduate program in the areas of mobile communications and telecommunications networks. Her research interests are in the field of mobile and personal communications, satellite and HAP communications, multiple access systems, routing and traffic flow in networks and QoS studies for multimedia applications over the Internet. She is involved in many national and international projects in these areas and she has chaired the European COST262 Action on Spread Spectrum Techniques. She has served as a member of the TPC of many IEEE/IEE conferences. She is a permanent reviewer for many international journals. She has published about 80 papers in refereed journals and conferences. She is a senior member of IEEE, currently chairing the joint IEEE VTS & AESS Chapter in Greece.     

A bandwidth reservation protocol for speech/data integration in TDMA-based advanced mobile systems

The traffic performance of third-generation mobile systems is greatly influenced by the multiple access protocols used in the radio access subsystem. The paper introduces an access protocol, SIR (Service Integration Radio Access), which has the potential for accommodating the requirements of speech and bursty data traffic in an efficient way. SIR is evolved from a protocol (PRMA ++) studied in the framework of a TDMA-based version of the European Universal Mobile Telecommunication System (UMTS) and uses dedicated mechanisms for data bandwidth request collection and servicing.     

Emulation platform for inter-domain protocols validation of integrated space-terrestrial network

The inter-domain routing protocol is a key factor in the rapid integration of various satellite systems and heterogeneous networks in integrated space-terrestrial network (ISTN).However,the wide difference between network topologies of space and terrestrial networks may present significant challenges to the deployment of existing inter-domain protocols.To test the performance of these protocols,an emulation platform for ISTN was designed to efficiently emulate the dynamic and large-scale space network and the existing terrestrial networks using virtual network technology.Extensive experiments demonstrate that,with the expansion of the scale of space network and the scale of terrestrial Internet’s routing table,the integration efficiency between space and terrestrial networks becomes very low.     

A quantitative comparison of multiple access control protocols forwireless 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 time different protocols compare against each other on a unified basis. In this paper, we quantitatively compare seven previously 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, DPRMMA, 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     

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     

Cognitive medium access control protocols for secondary users sharing a common channel with time division multiple access primary users

The unused time slots in a primary time division multiple access (TDMA) network are regarded as the potential channel access opportunities for secondary users (SUs) in cognitive radio (CR). In this paper, we investigate the medium access control protocols that enable SUs to access a common TDMA channel with primary users (PUs). The primary traffic is assumed to follow a Bernoulli random process. A two‐state Markov chain is used to model the secondary traffic, and two different scenarios are considered. The first scenario assumes that the secondary packet arrivals are independent and follow a Bernoulli random process and a cognitive carrier sensing multiple access (Cog‐CSMA) protocol is proposed. A Rayleigh fading channel is considered in evaluating Cog‐CSMA, and its throughput expression is derived in this paper. The second scenario assumes that the packet arrivals follow a correlated packet arrival process and a cognitive packet reservation multiple access (Cog‐PRMA) protocol is proposed. A Markov chain is used to model the different system states in Cog‐PRMA and derive the throughput. Numerical results show that the Cog‐CSMA and Cog‐PRMA protocols achieve the objective of supporting secondary transmissions in a TDMA network without interfering the PUs' transmissions and improve the network bandwidth utilization. Copyright © 2012 John Wiley & Sons, Ltd.