Assignment Multiple Access Research Articles

A General Framework of LSTM and Transfer Learning Based CFDAMA Strategy in Broadband Satellite System

With the development of the economy and technology, people’s requirement for communication is also increasing. Satellite networks have been paid more and more attention because of its broadband service capability and wide coverage. In this paper, we investigate the framework of a long-short term memory (LSTM) and transfer learning-based Combined Free/Demand Assignment Multiple Access (CFDAMA) scheme (CFDAMA-LSTMTL), which is a new multiple access scheme in the broadband satellite system. Generally, there is a delay time T between sending a request from the user to the satellite and receiving a reply from the satellite. So far, the traditional multiple access schemes has not processed the data traffic generated in this period of time. So, in order to transmit the data traffic in time, we propose a new prediction method, which combines LSTM with transfer learning. We introduce the prediction method into the CFDAMA scheme so that it can reduce data accumulation by the way of sending the sum slots requested by the user and the predicted request slots generated in the delay time T. A comparison with CFDAMA-PA and CFDAMA-PB is provided through simulation results, which gives the effect of the CFDAMA-LSTMTL in a broadband satellite systems.

A CLSTM and transfer learning based CFDAMA strategy in satellite communication networks.

With the development of the economy and technology, people’s requirement for communication is also increasing. Satellite communication networks have been paid more and more attention because of their broadband service capability and wide coverage. In this paper, we investigate the scheme of convolutional long short term memory (CLSTM) network and transfer learning (TL) based combined free/demand assignment multiple access (CFDAMA) scheme (CFDAMA-CLSTMTL), which is a new multiple access scheme in the satellite communication networks. Generally, there is a delay time T between sending a request from the user to the satellite and receiving a reply from the satellite. So far, the traditional multiple access schemes have not processed the data generated in this period. So, in order to transmit the data in time, we propose a new prediction method CLSTMTL, which can be used to predict the data generated in this period. We introduce the prediction method into the CFDAMA scheme so that it can reduce data accumulation by the way of sending the slots request which is the sum of slots requested by the user and the predicted slots generated in the delay time. A comparison with CFDAMA-PA and CFDAMA-PB is provided through simulation results, which gives the effect of the CFDAMA-CLSTMTL in a satellite communication network.

CFDAMA-SRR: A MAC Protocol for Underwater Acoustic Sensor Networks

Underwater acoustic sensor networks are an enabling technology for many applications. Long propagation delays and limited bandwidth of the acoustic channel place constraints on the trade-off between achievable end-to-end delay, channel utilization, and fairness. This paper provides new insights into the use of the combined free/demand assignment multiple access (CFDAMA) schemes. The CFDAMA can be classified as adaptive TDMA, where capacity is usually assigned on demand. The CFDAMA with round robin requests (CFDAMA-RRs) are shown to minimize end-to-end delay and maximize channel utilization underwater. It sustains fairness between nodes with minimum overhead and adapts to changes in the underwater channel and time-varying traffic requirements. However, its performance is heavily dependent on the network size. The major contribution of this paper is a new scheme employing the round robin request strategy in a systematic manner (CFDAMA-SRR). Comprehensive event-driven Riverbed simulations of a network deployed on the sea bed show that the CFDAMA-SRR outperforms its underlying scheme, CFDAMA-RR, especially when sensor nodes are widely spread. Considering node locations, the novel scheme has a bias against long delay demand assigned slots to enhance the performance of the CFDAMA-RR. The illustrative examples show good agreement between the analytical and simulation results.

A Multiple Access Protocol Based on Gray Forecast for Satellite Network

A satellite network’s multiple access protocol must be well designed to efficiently occupy channel resources and meet various qualities of service requirements. In this paper, a combined free/demand assignment multiple access protocol based on gray forecast is proposed. In terms of access, the adoption of the gray forecast method allows the user to book the number of timeslots to have more than the existing number of burst of packets. In terms of bandwidth allocation, a user priority allocation method is used to prioritize users with high needs and focus on the allocation of satellite resources. Experimental results show that the proposed protocol can effectively improve the channel utilization of the entire system. Thus, this protocol has some advantages over existing protocols in network throughput and end-to-end delay.

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.

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.

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.

Delivery of triple-play services over broadband satellite networks

Digital video broadcast return channel via satellite system (RCS) is a key European standard that specifies a broadband satellite system using dynamic capacity assignment and multi-frequency time-division multiple access. This study introduces new architectural components for an RCS system to support advanced Internet protocol (IP)-oriented multimedia. This will allow closer integration of satellite networks with the next generation of multimedia-enabled networks enabling operators to offer triple-play services that simultaneously support voice over IP, television-over IP and other services. These types of services are particularly suited to next generation satellite systems that combine transparent and multi-spot beam satellites with on-board regenerative signal processing, and can evolve to use adaptive coding and modulation.

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.

Dynamic capacity allocation for quality-of-service support in ip-based satellite networks

In broadband satellite access networks, the efficient management of the return channel transmission capacity is key in reducing the service cost while satisfying the QoS requirements of IP-based multimedia applications. In this article a dynamic capacity allocation scheme based on combined free/demand assignment multiple access is proposed, allowing the return channel capacity to be efficiently shared among many user terminals. Simulation results indicate that the proposed scheme provides adequate DiffServ IP QoS support while maintaining high satellite bandwidth utility and reduced DCA signaling overhead.

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.

Efficient integration of isochronous and data bursty traffics in low earth orbit‐mobile satellite systems

AbstractThis paper focuses on the radio resource management in low earth orbit‐mobile satellite systems (LEO‐MSSs) based on a time division multiple access (TDMA) air interface. A novel demand–assignment medium access control (MAC) protocol, named DRAMA+ (dynamic resource assignment multiple access—enhanced version), is proposed, where voice and Web traffic sources obtain transmission slots through requests sent by means of a random access phase. The round‐trip propagation delay (RTD) of LEO‐MSSs prevents an immediate feedback for each transmission attempt. Therefore, the main concern of the DRAMA+ scheme is to realize an efficient access phase. All the transmission requests successfully received at the satellite are managed by an on board scheduler. We have shown that DRAMA+ outperforms other techniques appeared in the literature in terms of voice quality, transmission delays for bursty data traffics and resource utilization. Moreover, a performance analysis of an ideal version of the DRAMA+ scheme has permitted us to prove the potentialities of the proposed DRAMA+ technique. Stability issues have been addressed as well as the impact on the DRAMA+ performance of the LEO satellite constellation RTD value. Copyright © 2002 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.

Bandwidth assignment scheme for ON-OFF type data traffic via satellite

A burst reservation multiple access (BRMA) scheme is presented, suited to carrying ON-OFF type data traffic via satellite. Its performance is compared with the combined free/demand assignment multiple access (CFDAMA) scheme and it is shown that the BRMA protocol can provide superior delay/utilisation performance of satellite channels.

Fair deterministic packet access protocol: F-RAMA (fair resource assignment multiple access)

The RAMA (resource auction multiple access) protocol uses a scheme where the access procedure is divided into fixed length cycles. A variation of RAMA, the tree-search resource auction multiple access (TRAMA) protocol, was proposed to reduce the length cycle. Both protocols present disadvantages, although different ones. The authors propose and evaluate another variation of RAMA, fair resource assignment multiple access (F-RAMA). Simulation methods were used to calculate packet dropping probability, access delay and statistics of speech clipping in voice transmission.