Demand Assignment Multiple Access Research Articles

Random access schemes for satellite networks, from VSAT to M2M: a survey

SummaryIn this survey paper, we review the random access (RA) techniques with particular emphasis on the issues and the possible solutions applicable to satellite networks. RA dates back to the 1970s when the ALOHA protocol was developed to solve the problem of interconnecting university computers located in different Hawaiian islands. Since then, several evolutions of the ALOHA protocol have been developed. In particular, solutions were devised to mitigate the problem of packet collisions severely degrading the RA protocols performance. The approach followed for many years has been to avoid the occurrence of collisions rather than solving them. More recently, techniques tackling the RA packet collision problem have appeared triggered by the need of improving RA performance in satellite and terrestrial wireless networks. In particular, satellite networks large propagation delay does not allow the adoption of enhanced terrestrial RA techniques based on channel sensing. Adopting conventional demand assignment multiple access protocols is not suitable for supporting a large number of sensors or devices transmitting small‐size low duty cycle packets as required for machine‐to‐machine communications. This provided the stimulus to exploit successive interference cancelation schemes to solve packet collision issues. The use of successive interference cancelation in RA is relatively new and has opened up a promising research area. We provide an extensive review of recent high‐performance RA techniques achieving more than three orders of magnitude throughput increase compared with the original ALOHA at low packet loss rate. In this survey, we cover both slotted and unslotted techniques. Finally, we review the use of RA in satellite systems and related standards including recent proposals for machine‐to‐machine applications. Copyright © 2016 John Wiley & Sons, Ltd.

Rapidly Gathering Iinformation in Wireless Sensor Networks using Demand Assigned Multiple Access (DAMA) with Multiple Access Collision Avoidance (MACA)

Rapidly Gathering Iinformation in Wireless Sensor Networks using Demand Assigned Multiple Access (DAMA) with Multiple Access Collision Avoidance (MACA)

Innovative DAMA algorithm for multimedia DVB-RCS system

Abstract Satellite is often used as an access network in the Next Generation Networks landscape, where multimedia and real-time services are supported by return channels. However, these satellite return channels are a very limited resource with many terminal stations competing for its use, making its efficient assignation one of the key problems to solve in order to increase network performance. This article presents an innovative implementation of the resource allocation mechanism demand assigned multiple access (DAMA) applied to satellite return channel assignment, which provides support for dynamic allocation and quality-of-service. This resource allocation mechanism has been validated with the special purpose advanced Internet network emulator, using the test lab implementation to optimize traffic mapping and queue parameters directly in the field. The numerical results for the different test cases considered are presented, showing that the DAMA algorithm provided is an efficient way of assigning resources, and also helping in the comparison of the different capacity request mechanisms described in the standard.

Performance Measures Of Wireless Protocols For Atm Networks

The concept of wireless ATM is now being actively considered as a potential framework for nextgeneration wireless communication networks capable of supporting integrated multimedia services with different QoS requirements. Several key subsystem design issues for wired ATM and wireless networks needs to be readdressed in the scope of the wireless ATM, which has the capability to extend the statistical multiplexing of wired ATM network into the wireless medium. One of the key subsystem issues is the development of appropriate medium access control (MAC) protocol. The extension of the ATM network into wireless environment faces many interesting problems. The original ATM network was designed for high speed, noiseless, and reliable channels. None of these characteristics are applicable to the wireless channel. One of the critical aspects of a wireless ATM network is the Medium or Multi Access Control (MAC) Protocol used by the Mobile station (MS) to request service from the BS, which has to consider the Quality of Service (QoS) of the specific applications. This paper analyses recently proposed MAC protocols, particularly those of Demand Assignment Multiple Access protocols using TDMA technique with Frequency Division Duplex (FDD). It also gives performance measures of two best suited protocols for wireless network environment Distributed Queuing Request Update Multiple Access (DQRUMA) protocol and Adaptive Request Channel Multiple Access (ARCMA) protocol.

MF-TDMA DAMA 방식 위성 망에서 효율적인 자원할당 시스템 설계

본 논문에서는 MF-TDMA (Multi Frequency-Time Division Multiple Access) DAMA (Demand-Assigned Multiple Access) 방식을 사용하는 위성 망에서 지상 단말이 네트워크 제어기에게 자원을 요청할 때, 자신에게 유입되어지는 트래픽에 대한 이전 정보(History) 즉, 트래픽 발생 패턴이나 트래픽 종류 등을 바탕으로 자원을 요청하고, 네트워크 제어기는 지상 단말들이 이전에 요청했던 정보(History)를 바탕으로 보다 효율적으로 위성 자원을 할당하여 위성 망 자원 할당 시간의 지연으로 인한 다량의 데이터 폐기를 최대한 억제하기 위한 MF-TDMA DAMA 방식 위성 시스템을 설계하였다. 미군의 전략적 군사 정보망 (Warfighter Information Network-Tactical, WIN-T) 커뮤니티에서는 L-3 Linkabit 다중 주파수-시간 분할 다중 접속 (MF-TDMA) 요청에 의해 할당되어지는 다중 접속 (DAMA) 네트워크 중심 파형 (Network Centric Waveform, NCW)을 full-mesh IP over SHF 위성 통신을 위한 네트워크 표준으로 선택하였다. MF-TDMA 위성 망에서는 네트워크 제어기(Network Controller, NC)가 최대 255개의 지상 단말들 (Earth Terminals, ETs)의 주기적인 자원요청에 대하여 동적으로 위성 망 자원을 할당하여 단말들 간의 통신을 가능하도록 한다. In this paper, I designed the satellite system, using the MF-TDMA (Multi Frequency-Time Division Multiple Access) DAMA (Demand-Assigned Multiple Access) method, that allocates the satellite resources more effectively to prevent a large quantity data discard when Earth Terminals (ETs) request their satellite network resource to Network Controller (NC) by using their history information, such as traffic pattern or traffic class which have been receiving, and the network controller allocates the satellite network resource and send to earth terminals by using his history information that earth terminals have been requested already. The U.S. Military Warfighter Information Network-Tactical (WIN-T) community has selected the L-3 Linkabit MF-TDMA DAMA Network Centric Waveform (NCW) as the networking standard for full-mesh IP over SHF satellite communications. In the MF-TDMA DAMA satellite network, network controller allocates the satellite network resources and enables maximum 255 earth terminals to communicate each other for periodic satellite network resource requests of earth terminals.

Dynamic Leveling Scheme for Traffic Prediction in Satellite Networks

We propose a new resource prediction method for the Demand Assigned Multiple Access (DAMA) scheme in satellite networks. Inaccurate prediction of future traffic causes degradation of QoS and utilization due to the long delay in satellite networks. The Dynamic Leveling Scheme (DLS) use a leveling method to modify its prediction to a discrete one to change the precision of the prediction result. This new scheme has two features: 1) It enhances the probability of successful prediction and 2) it can be applied to any type of existing prediction method. Simulations show enhanced utilization and performance of the satellite link.

Analysis and Performance Evaluation of a Burst-Based TCP for Satellite DVB RCS Links

ESA Satlabs proposed a splitting architecture, named Interoperable-Performance Enhancing Proxy (I-PEP), which defines a protocol stack for the edges of a Digital Video Broadcasting-Return Channal over Satellite (DVB-RCS) link with the aim of improving performance of Transmission Control Protocol (TCP)-based applications. At the transport layer of I-PEPs, the Space Communications Protocols Standards-Transport Protocol (SCPS-TP) provides a reliable connection to upper layers, although resulting in very poor performance in tests. In fact, standard congestion-control mechanisms under-perform mainly due to long latency and Demand Assignment Multiple Access (DAMA) access schemes, especially in the case of short transfers, as for Web traffic, when optimum window may not be reached. In this paper, a burst-based TCP, named TCP Noordwijk (TCPN), is introduced to improve on these aspects. To evaluate performance, the protocol has been implemented on the Network Simulator NS-2. Definitively, details on the protocol design, implementation, and a vast gamut of results coming from simulations are reported.

Performance evaluation of TCP‐based applications over DVB‐RCS DAMA schemes

AbstractTransmission Control Protocol (TCP) performance over Digital Video Broadcasting—Return Channel via Satellite (DVB‐RCS) standard is greatly affected by the total delay, which is mainly due to two components, propagation delay and access delay. Both are significant because they are dependent on the long propagation path of the satellite link. The former is intrinsic and due to radio wave propagation over the satellite channel for both TCP packets and acknowledgements. It is regulated by the control loop that governs TCP. The latter is due to the control loop that governs the demand assignment multiple access (DAMA) signalling exchange between satellite terminals and the network control center, necessary to manage return link resources. DAMA is adopted in DVB‐RCS standard to achieve flexible and efficient use of the shared resources. Therefore, performance of TCP over DVB‐RCS may degrade due to the exploitation of two nested control loops also depending on both the selected DAMA algorithm and the traffic profile.This paper analyses the impact of basic DAMA implementation on TCP‐based applications over a DVB‐RCS link for a large set of study cases. To provide a detailed overview of TCP performance in DVB‐RCS environment, the analysis includes both theoretical approach and simulation campaign. Copyright © 2009 John Wiley & Sons, Ltd.

Fair Adaptive Bandwidth and Subchannel Allocation in the WiMAX Uplink

In some modern communication systems, as it is the case of WiMAX, it has been decided to implement Demand Assignment Multiple Access (DAMA) solutions. End-users request transmission opportunities before accessing the system, which provides an efficient way to share system resources. In this paper, we briefly review the PHY and MAC layers of an OFDMA-based WiMAX system, and we propose to use a Network Utility Maximization (NUM) framework to formulate the DAMA strategy foreseen in the uplink of IEEE 802.16. Utility functions are chosen to achieve fair solutions attaining different degrees of fairness and to further support the QoS requirements of the services in the system. Moreover, since the standard allocates resources in a terminal basis but each terminal may support several services, we develop a new decomposition technique, the coupled-decompositions method, that obtains the optimal service flow allocation with a small number of iterations (the improvement is significant when compared to other known solutions). Furthermore, since the PHY layer in mobile WiMAX has the means to adapt the transport capacities of the links between the Base Station (BS) and the Subscriber Stations (SSs), the proposed PHY-MAC cross-layer design uses this extra degree of freedom in order to enhance the network utility.

A Cross-Layer Approach to Enhance QoS for Multimedia Applications Over Satellite

The need for on-demand QoS support for communications over satellite is of primary importance for distributed multimedia applications. This is particularly true for the return link which is often a bottleneck due to the large set of end-users accessing a very limited uplink resource. Facing this need, Demand Assignment Multiple Access (DAMA) is a classical technique that allows satellite operators to offer various types of services, while managing the resources of the satellite system efficiently. Tackling the quality degradation and delay accumulation issues that can result from the use of these techniques, this paper proposes an instantiation of the Application Layer Framing (ALF) approach, using a cross-layer interpreter (xQoS-Interpreter). The information provided by this interpreter is used to manage the resource provided to a terminal by the satellite system in order to improve the quality of multimedia presentations from the end user's point of view. Several experiments are carried out for different loads on the return link. Their impact on QoS is measured through different application as well as network level metrics.

Burst Targeted Demand Assignment Multiple-Access for Broadband Internet Service Delivery Over Geostationary Satellite

This paper presents a detailed performance evaluation of the burst targeted demand assignment multiple-access (BTDAMA) schemes, which employ an original approach to implementing demand assignment multiple-access (DAMA), suited to supporting ON/OFF type traffic over a broadband geostationary satellite link. A novel analytical model is introduced which can be used to predict and evaluate the delay performance of rate-based medium access control schemes, and is applied to BTDAMA to investigate the potential performance enhancements offered by introducing free assigned capacity to the scheme. Results show that BTDAMA eliminates the end-to-end delay bound of traditional DAMA techniques, offering significantly superior performance compared with conventional schemes, with free assignment effective in improving the delay performance for a wide range of traffic burst durations.

An IP‐based satellite communication system architecture for interactive multimedia services

AbstractThe paper presents an IP‐based broadband satellite access (BSA) network architecture for interactive multimedia services with an emphasis on the return link (upstream direction). Dynamic capacity allocation (DCA) strategies based on the Combined Free and Demand Assignment Multiple Access (CFDAMA) scheme to support the Digital Video Broadcasting‐Return Channel via Satellite (DVB‐RCS) standard and Differentiated Services (DiffServ) architecture in order to achieve short delay and different QoS requirements are proposed. DCA scheduling algorithms and multiple‐queue user terminal structures are presented. Simulation results on the traffic performance for various traffic loads, types and conditions confirm the effectiveness of the proposed structures. Copyright © 2003 John Wiley & Sons, Ltd.

A predictive demand assignment multiple access protocol for Internet access over broadband satellite networks

AbstractMedium access control (MAC) protocol is responsible for wireless resource management, which is crucial to satellite communication. To enhance the performance of broadband satellite networks, the application characteristics should be considered in the design of the MAC protocol. With the rapid expansion of Internet applications and the attractiveness of high speed Internet access via broadband satellite networks, it becomes an attractive objective to take into account the self‐similar nature of Internet traffic in MAC protocol designs. This paper presents a novel predictive demand assignment multiple access (PRDAMA) protocol for packet communications over broadband satellite networks. PRDAMA allocates free bandwidth resources by estimating the positive varying trend of the Internet traffic to facilitate prediction of the bandwidth requirements of the earth stations. Simulation results demonstrate that PRDAMA achieves a lower average delay and delay jitter compared with other DAMA protocols under highly bursty traffic due to its accurate traffic trend prediction. With less bursty traffic, PRDAMA still performs better than the other DAMA protocols under a heavy traffic load. Copyright © 2003 John Wiley & Sons, Ltd.

An Interval-Based Scheduling Algorithm for Optical WDM Star Networks

This paper considers scheduling algorithms for multiple access protocols associated with wavelength division multiplexed (WDM) multi-channel optical networks based on the star topology. To share the available channels among nodes, several demand assignment multiple access protocols based on reservation schemes have been proposed. The core of such reservation-based protocols is the scheduling algorithm, which allocates channels and time slots to the nodes based on traffic demand. The key objectives of the scheduling algorithm design are maximization of network utilization and minimization of packet delay. There is a trade-off between these two requirements: it takes more computation time to achieve a better utilization, which in turn will increase packet delay. This trade-off directly affects the overall network performance. Another important requirement is the consideration of transceiver tuning latencies. In this paper, we propose an on-line scheduling algorithm called OIS (On-line Interval-based Scheduling) to balance these requirements and increase network throughput. We also require that the scheduling algorithms be simple so that hardware implementation is feasible to reduce overall delay. We compare our scheduling algorithm to the Transmission Assignment Algorithm (TAA) studied by Borella and Mukherjee (1996); and to a matrix decomposition algorithm studied by Sivalingam and Wang (1996). We show that our algorithm, although suffering from small utilization loss, requires significantly less computation time and results in higher network throughput. In particular, for higher network speeds such as 2.4 Gbps per channel, the potential improvement using our algorithm is substantial. We also provide conditions when either protocol performs better compared to the other.

Weighted fair bandwidth-on-demand (WFBoD) for geostationary satellite networks with on-board processing

More and more network operators plan to use broadband satellite systems as part of their global broadband multimedia infrastructure because of their large geographic coverage, inherent broadcast capabilities, and fast deployment features. The recent advances on Ka-band transmission, fast on-board switching, and spot beam technologies mean that satellites can be employed efficiently to help provide high-speed, global connectivity to users all around the world. Satellites are multiple access systems with very limited transmission capacity compared to terrestrial network nodes. Therefore, end-to-end resource management for such systems is key to deliver acceptable quality of service to services while providing adequate efficiency (i.e., a level of grade of service that entails the use of such systems). In this paper we present a demand assignment multiple access based resource management protocol, weighted fair bandwidth-on-demand (WFBoD), for geostationary satellite networks with on-board processing. WFBoD combines flexibility with efficiency and the “right” level of traffic segregation. We formulate the global resource allocation problem central to which is a large “generic” integer value optimization problem with a large number of coupled constraints. We propose heuristics to solve this optimization problem and compare their performances and their complexity with the formal solution.

Resource management for ATM-based geostationary satellite networks with on-board processing

This paper deals with medium access control (MAC) and congestion control protocols for ATM-based geostationary satellite networks, where some demand assignment multiple access (DAMA) functionalities are performed on-board. The proposed resource management has been designed for the lower priority ATM traffic categories, which have to adapt themselves to the traffic conditions. The novelties proposed in this paper consist of a resource management strategy based on two levels of aggregations of the virtual channel connections and of a DAMA algorithm for generating the terminal bandwidth requests exploiting control theory concepts. These two innovative features are combined with an existing congestion control algorithm and an existing DAMA algorithm for assigning the capacity based on terminal requests. The resulting resource management achieves the goals of avoiding on-board congestion situations, guaranteeing an efficient use of the satellite resources and limiting the on-board processing complexity. Software simulations have been performed with the OPNET tool, in order to test the effectiveness of the proposed protocols.

An IP transport and routing architecture for next-generation satellite networks

Over the past several years, a number of new satellite systems have been proposed to provide high-speed Internet and multimedia services to businesses and home users. These proposals have been driven by the desire of network operators to reach end users that do not have cost effective access to other alternatives such as fiber, DSL, and cable, and by the availability of new spectrum (Ka-band) for use by new satellite services. The proposed systems generally employ multiple high-power spot beams, an onboard fast packet switch, and a demand-assigned multiple access scheme to provision IP-based services. In this article we concentrate on a geosynchronous satellite system where packet transport and switching within the satellite system are based on ATM. We describe an IP/ATM interworking and IP routing architecture that is driven by three main requirements: (1) the ability to support ATM SVCs between hundreds of thousands of satellite terminals by a single ATM switch located onboard; (2) a scalable IP routing architecture that does not result in large volumes of routing traffic to be transported over the satellite; and (3) the ability to segment the satellite terminals for routing and administrative control by ISPs and enterprise networks.

Channel access and interference issues in multi-code DS-CDMA wireless packet (ATM) networks

Multi-Code Direct-Sequence Code-Division-Multiple-Access (MC-CDMA) has been proposed as a flexible multiple access scheme for wireless packet networks that support a large variety of mobiles with different and even time-varying rates. Using MC-CDMA, traffic streams with significantly different transmission rates can be easily integrated into a unified architecture, with all the transmissions occupying the same bandwidth and having the same spread spectrum processing gain. In this paper, we address medium-access and interference issues in MC-CDMA wireless packet networks. For medium access, we propose and study Multi-Code CDMA (MC-CDMA) with Distributed-Queueing Request Update Multiple Access (DQRUMA) to form a unified bandwidth-on-demand fair-sharing platform for multi-rate wireless services. DQRUMA is an efficient demand-assignment multiple access protocol for wireless access and scheduling. Pseudo-Noise (PN) codes (primary codes) and optimal power levels are allocated to the mobiles on a slot-by-slot basis, and a Maximum Capacity Power Allocation (MCPA) criterion exploits the sub-code concatenation property of the MC-CDMA transmission. Simulation results show that the system provides close to ideal-access performance for multi-rate mobiles, both with homogeneous traffic characteristics and with a mix of heterogeneous traffic characteristics. Finally, we analyze the effects of MC-CDMA intercell interference on the reverse link (i.e., mobile to cell site) and investigate interference reduction by using the Maximum Capacity Power Allocation (MCPA) criterion. Our results show significant reduction in reverse-link MC-CDMA intercell interference is possible using the MCPA criterion.

PERFORMANCE OF COMBINED FREE/DEMAND ASSIGNMENT MULTIPLE‐ACCESS SCHEMES IN SATELLITE COMMUNICATIONS

By combining free assignment with demand assignment, the combined free/demand assignment multiple-access (CFDAMA) protocol offers a much shorter delay at low and medium traffic loads while maintaining the high channel utility of the demand-assignment multiple-access (DAMA) technique. In these schemes, reservation can be made using pre-assigned (PA) or random-access (RA) request slots, or piggy-backing (PB) the request on a data packet. This paper presents a performance analysis of CFDAMA schemes in packet satellite communications. Illustrative examples are given. They show a good agreement between analytical and simulation results. For low and medium sizes of terminal population, the CFDAMA-PA scheme has an excellent delay-throughput performance. As the terminal population increases, its performance is gradually degraded due to the long waiting time for a request. For a very large number of terminals, the CFDAMA-RA becomes more effective than CFDAMA-PA. This indicates that a CFDAMA scheme using a hybrid PB/RA requesting protocol can provide the best performance for a wide range of terminal population sizes.

PERFORMANCE OF COMBINED FREE/DEMAND ASSIGNMENT MULTIPLE-ACCESS SCHEMES IN SATELLITE COMMUNICATIONS

By combining free assignment with demand assignment, the combined free/demand assignment multiple-access (CFDAMA) protocol offers a much shorter delay at low and medium traffic loads while maintaining the high channel utility of the demand-assignment multiple-access (DAMA) technique. In these schemes, reservation can be made using pre-assigned (PA) or random-access (RA) request slots, or piggy-backing (PB) the request on a data packet. This paper presents a performance analysis of CFDAMA schemes in packet satellite communications. Illustrative examples are given. They show a good agreement between analytical and simulation results. For low and medium sizes of terminal population, the CFDAMA-PA scheme has an excellent delay-throughput performance. As the terminal population increases, its performance is gradually degraded due to the long waiting time for a request. For a very large number of terminals, the CFDAMA-RA becomes more effective than CFDAMA-PA. This indicates that a CFDAMA scheme using a hybrid PB/RA requesting protocol can provide the best performance for a wide range of terminal population sizes.