Satellite ATM Research Articles

Development of Global Geographical Coverage Area for Terrestrial Networks Internetworked with Leo Satellite Network

Network planning, analysis and design are an iterative process aimed at ensuring that a new network service meets the needs of subscribers and operators. During the initial start-up phase, coverage is the big issue and coverage in telecommunications systems is related to the service area where a bare minimum access in the wireless network is possible. In order to guarantee visibility of at least one satellite above a certain satellite elevation, more satellites are required in the constellation to provide Global network services. Hence, the aim of this paper is to develop wide area network coverage for sparsely distributed earth stations in the world. A hybrid geometrical topology model using spherical coordinate framework was devised to provide wide area network coverage for sparsely distributed earth stations in the world. This topology model ensures Global satellite continuous network coverage for terrestrial networks. A computation of path lengths between any two satellites put in place to provide network services to selected cities in the world was carried out. A consideration of a suitable routing decision mechanism, routing protocols and algorithms were considered in the work while the shortest paths as well as the alternate paths between located nodes were computed. It was observed that a particular satellite with the central angle of 27° can provide services into the diameter of the instantaneous coverage distance of 4081.3 Km which is typical of wide area network coverage. This implies that link-state database routing scheme can be applied, continuous global geographical coverage with minimum span, minimum traffic pattern and latency are guaranteed. Traffic handover rerouting strategies need further research. Also, traffic engineering resources such as channel capacity and bandwidth utilization schemes need to be investigated. Satellite ATM network architecture will benefit and needs further study.

An operation system for unitary management of network schedule information on multiple platforms

AbstractThis paper considers multiple communication platforms and discusses an operation system that performs unitary management of network operations. With the recent advent of diversified communication configurations, there is an increasing demand toward communication service over multiple platforms, and it is logical that end‐to‐end network management should be handled in a unitary and efficient way. In the conventional network operation management technique with multiple platforms, the ordinary approach is to use concentrated management, which, however, produces problems in versatility and reliability. From this viewpoint, the operation method combining concentrated and distributed management methods is considered in the proposed operation system in an attempt to overcome the problems. The proposed system is applied to a digital video transmission communication system using a satellite communications network and ATM communications network. The proposed operation method is evaluated by using the newly developed system and its effectiveness in terms of reliability and the like is verified. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(13): 67–77, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20414

A combined admission control algorithm with DA protocol for satellite ATM networks

Admission control is an important strategy for Quality of Service (QoS) provisioning in Asynchronous Transfer Mode (ATM) networks. Based on a control-theory model of resources on-Demand Allocation (DA) protocol, the paper studies the effect of the protocol on the statistical characteristics of network traffic, and proposes a combined connection admission control algorithm with the DA protocol to achieve full utilization of link resources in satellite communication systems. The proposed algorithm is based on the cross-layer-design approach. Theoretical analysis and system simulation results show that the proposed algorithm can admit more connections within certain admission thresholds than one that does not take into account the DA protocol. Thus, the proposed algorithm can increase admission ratio of traffic sources for satellite ATM networks and improve satellite link utilization.

Buffer management optimization strategy for satellite ATM

Abstract ECTD (erroneous cell tail drop), a buffer management optimization strategy is suggested which can improve the utilization of buffer resources in satellite ATM (asynchronous transfer mode) networks. The strategy, in which erroneous cells caused by satellite channel and the following cells that belong to the same PDU (protocol data Unit) are discarded, concerns non-real-time data services that use higher layer protocol for retransmission. Based on EPD (early packet drop) policy, mathematical models are established with and without ECTD. The numerical results show that ECTD would optimize buffer management and improve effective throughput (goodput), and the increment of goodput is relative to the CER (cell error ratio) and the PDU length. The higher their values are, the greater the increment. For example, when the average PDU length values are 30 and 90, the improvement of goodput are respectively about 4% and 10%.

Adaptive CDV Compensation Algorithm for Satellite Networks

In this paper, we propose an adaptive compensation algorithm to compensate cell delay variation (CDV) occurring during ATM/TDMA transition in a satellite ATM network. The proposed CDV compensation algorithm uses two types of additional information: cell position information (Cp)indicating the number of cells (N) arriving within a control unit time (Tc) and positions of cells at a given time-and the number of cells in bursts-to take into account the characteristics of localized bursts. To evaluate the performance of the proposed algorithm, we performed a computer simulation based on an OPNET environment, using the Markov modulated Poisson process (MMPP) traffic model and assessed its effectiveness from varied standpoints. The results of the performance testing indicate that the proposed algorithm, while requiring significantly less additional information than previous CDV compensation algorithms, is able to more efficiently compensate CDV in localized burst traffic than the previous ones.

Optimal routing in non-geostationary satellite ATM networks with intersatellite link capacity constraints

The trend toward broadband communications in space is foreseeable, and its features predestine ATM as the basic mode of operation. Some of the low and medium earth orbit satellite concepts make use of intersatellite links (ISLs) to provide global connectivity with minimal usage of terrestrial fixed network resources. Interconnecting neighbouring satellites with ISLs results in a partially meshed switching subnetwork in space. The ISLs have a time-varying distance or may even lose sight of each other. This feature of the ISL topology dynamics significantly increases the complexity of connection-oriented network operation and routing. We deal with the routing problem to minimize the virtual path connection handover rate and path delay in the time-varying ISL subnetwork topology with ISL capacity constraints. A heuristic algorithm is proposed to deal with this problem, which is based on Lagrangean relaxation and dynamic programming. When there is sufficient capacity at every ISL, the algorithm produces an optimal solution easily using only dynamic programming. For evaluation of our algorithm, some computational results have been presented. These results show that our optimization algorithm can produce a solution close to an optimal solution when there exist ISL capacity constraints.

Congestion control for ABR traffic in satellite networks

The ABR service suffers greatly from the long propagation delays typical of satellite networks. It has, in fact, been shown that a long delay, in combination with a high bandwidth, can deceive ABR sources and make them believe that a break has occurred somewhere along the path. ABR sources respond to breaks by reducing their cell rate, so resource utilization decreases drastically. The solution to this problem has been to reduce the cell rate only when feedback from the network has been missing for a period longer than the round trip delay. However, this delay in reducing the cell rate causes many additional cell losses if a break actually occurs. In this paper, a framework is introduced for ABR traffic control in satellite ATM networks. The framework is composed of an accurate analytical model for standard ABR traffic behavior in long propagation delay networks, and new procedures which avoid false decreases in the cell rate. The analytical model is used to forecast false decreases of the cell rate and trigger the new procedures. Overall, the proposed framework avoids a reduction in network utilization without causing additional losses.

Unicast and multicast IP error performance over an ATM satellite link

IP multicast using ATM-based satellites provides the potential to support multimedia applications, including audio/video streaming and information distribution, at a large scale. This article considers the impact of satellite channel errors, and equations are derived for the probability of IP datagram loss in the presence of burst errors on the satellite link. When there are a large number of multicast receivers per spotbeam there is a significant probability that one or more recipients will not receive the data, and this has implications particularly for the design of reliable multicast network protocols.

Multimedia Satellite Networks and TCP/IP Traffic Transport

To meet an increasing demand for multimedia services and electronic connectivity across the world, satellite networks will play an indispensable role in the deployment of global networks. A number of satellite communication systems have been proposed using geosynchronous (GEO) satellites, medium earth orbit (MEO) and low earth orbit (LEO) constellations operating in the Ka-band and above. At these frequencies, satellite networks are able to provide broadband services requiring wider bandwidth than the current services at C or Ku-band. Most of the next-generation broadband satellite systems will use ATM or "ATM-like" switching with onboard processing to provide full two-way services to and from earth stations. The new services gaining momentum include mobile services, private intranets, and high-data-rate internet access carried over integrated satellite-fiber networks. Several performance issues need to be addressed before a transport layer protocol like TCP can satisfactorily work over satellite ATM for large delay-bandwidth networks. The authors review the proposed satellite systems and discuss challenges such as traffic management and QoS requirements for broadband satellite ATM networks. The performance results of TCP enhancements for Unspecified Bit Rate over ATM (ATM-UBR+) for large bandwidth-delay environments with various end system policies and drop policies for several buffer sizes are presented.

A millimeter wave broadband wireless access technology demonstrator for the next generation Internet network reach extension

We report design and implementation scenarios for a gigabit-capacity and high-data-rate fixed wireless access technology demonstrator. The system is based on a broadband wireless access concept and implementation techniques utilizing millimeter-wave and newly introduced free-space optical wireless high-speed links. The demonstration platform is to provide broadband "last mile" access and networking solutions to Internet users in densely populated areas with homes and businesses (e.g., building-centric and inner city environments) in need of high bandwidth not served by the fiber infrastructure. The investigation focuses on the radio link design, network architecture, system integration, and a compatible interface to the existing ATM fiber and satellite core networks in support of the next-generation Internet (NGI) reach network extension by the wireless technology.

Throughput–complexity trade-off for ABR traffic in an ATM satellite network under cell loss constraints

This work refers to an ATM satellite system, supporting different QoS classes via the standard ATM traffic categories, i.e. Constant Bit Rate (CBR), Variable Bit Rate (VBR), Available Bit Rate (ABR) and Unspecified Bit Rate (UBR). The focus of this work is on ABR (i.e. closed loop control) and the central issue is to find trade-offs between a high ABR throughput and processing burden/buffer space required on board satellite, under the constraint that no buffer overflow occurs. ABR fairness issues are not central to this work and hence are not considered. The focus of the paper is to evaluate how adaptive prediction of higher priority CBR/VBR traffic can enhance ABR traffic performance, with respect to a simpler worst case based approach. Results show that a significant improvement of performance can be obtained even with rather straightforward prediction algorithms.

Central limit approximation approach for connectionadmission control in broadband satellite systems

The transient cell loss ratio (CLR) is investigated as a quality of service (QoS) measure for ATM satellite systems. To determine the QoS measure, a central limit approximation is proposed for a bufferless fluid model. The proposed approximation scheme is a promising approach for real-time connection admission control (CAC).

Improving the delay performance of ‘besteffort’ traffic over ATM satellite networks

A scheduling scheme for multimedia traffic over ATM-based TDMA satellite networks is proposed. This scheduling scheme is based on controlled alternation of the priorities of the best effort and delay sensitive connections in the scheduling process. Simulation experiments show that the delay performance of best effort connections is greatly enhanced with minimal effect on the cell loss performance of delay sensitive connections.

The development of performance and availability standards for satellite ATM networks

ATM services can be transported successfully over satellites provided adequate consideration is given to the specific characteristics of satellite communication systems and their interoperability with the terrestrial network. To establish end-to-end performance and availability standards, the ITU has developed recommendations for ATM intended to provide the quality of service and availability required by the end user. This article discusses the work of ITU-R Working Party 4B in developing recommendations that deal with the performance of ATM over satellites and with the availability objectives for ATM transport over satellites. Several issues are also identified for future work, in particular those pertaining to the characteristics of the new proposed satellites (LEOs, MEOs, GEOs) that will operate at frequencies higher than 15 GHz and those that plan to deploy ATM onboard processing or switching and intersatellite links.

A review of error performance models for satellite ATM networks

ITU-T Recommendations G.826 and 1.356 set the basis for error performance standardization at the lower layers of B-ISDN networks. The specific performance parameters of these recommendations are directly related to the bit error rate and are strongly dependent on the level of correlation of the error sequence. Bit errors in typical satellite transmissions occur in bursts, and that should be taken into account when designing satellite ATM networks. Error modeling and analysis of G.826 and 1.356 performance criteria and satellite design principles are reviewed.

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.

Satellite‐ATM networking and call performance evaluation for multimedia broadband services

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. In this paper, we investigate the design issues for the satellite protocol architecture that best satisfies the interconnection to the Broadband Integrated Services Digital Network (B-ISDN). The latest developments in broadband satellite communications aim to support a wide range of applications. These systems are designed to provide high quality multimedia services to remote user terminals. Furthermore, the mechanism that needs to be implemented in order to satisfy certain Grade Of Service (GoS) and Quality Of Service (QoS) criteria is discussed. A new methodology for the call performance evaluation of the Available Bit Rate (ABR) service class in a satellite Asynchronous Transfer Mode (ATM) network is proposed. Results at call level for different mix of service classes are presented using both analytical and simulation models. The simulation model was developed using OPNET modeller and it was used to record statistics that cannot be easily obtained by analysis. Copyright © 1999 John Wiley & Sons, Ltd.

Satellite-ATM networking and call performance evaluation for multimedia broadband services

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. In this paper, we investigate the design issues for the satellite protocol architecture that best satisfies the interconnection to the Broadband Integrated Services Digital Network (B-ISDN). The latest developments in broadband satellite communications aim to support a wide range of applications. These systems are designed to provide high quality multimedia services to remote user terminals. Furthermore, the mechanism that needs to be implemented in order to satisfy certain Grade Of Service' (GoS) and Quality Of Service (QoS) criteria is discussed. A new methodology for the call performance evaluation of the Available Bit Rate (ABR) service class in a satellite Asynchronous Transfer Mode (ATM) network is proposed. Results at call level for different mix of service classes are presented using both analytical and simulation models. The simulation model was developed using OPNET modeller and it was used to record statistics that cannot be easily obtained by analysis.

Next-generation satellite networks: architectures and implementations

A new generation of satellite networks is being developed to handle highly bursty Internet and multimedia traffic. In these networks, satellite links are used for interconnecting remote network segments as well as for providing direct network access to homes and businesses. In this environment, the satellite network must support not only circuit switched traffic, but also packet services with highly bursty traffic patterns. The traditional circuit switched approach based on the user or network signaling is inadequate to carry dynamically varying packet traffic efficiently, necessitating faster bandwidth allocation solutions. Standard interworking solutions and air interfaces are very important for interoperability leading to proliferation of satellite networks to potentially millions of home and business users. In this article we provide an overview of the standardization effort that has started at the TIA in the area of satellite ATM networks. Subsequently, a bandwidth-on-demand multiservice satellite network architecture implementation is described.

Traffic management for TCP/IP over satellite ATM networks

Several Ka-band satellite systems have been proposed that will use ATM technology to seamlessly transport Internet traffic. The ATM UBR, GFR, and ABR service categories have been designed for data. However, several studies have reported poor TCP performance over satellite ATM networks. We describe techniques to improve TCP performance over satellite ATM networks. We first discuss the various design options available for TCP end systems, IP-ATM edge devices, as well as ATM switches for long-latency connections. We discuss buffer management policies, guaranteed rate services, and the virtual source/virtual destination option in ATM. We present a comparison of ATM service categories for TCP transport over satellite links. The main goal of this article is to discuss design and performance issues for the transport of TCP over UBR, GFR, and ABR services for satellite ATM networks.