ISSN:0737-2884    

DOI:10.1002/sat.4600120302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0737-2884    

DOI:10.1002/sat.4600120303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractDesigning a world‐wide satellite network that consists of hundreds of user sites and thousands of circuit connections is a complex problem, which involves selecting a set of candidate satellites and satellite beams/frequency bands from among numerous existing and planned satellites, evaluation of circuit connectivity, earth‐station compatibility and sizing, and estimating transponder loading. The design process may also require assessment of the impact of a different set of satellites and modified user traffic requirements on the space segment, the earth‐station types and quantity, and the total system cost. Although a conventional design approach based on link‐by‐link and site‐by‐site analysis provides accurate results, it is time‐consuming and impractical for developing high‐level network architectures in a time‐constrained environment. A design technique is proposed which employs a set of rules for satellite network design, in combination with extensive databases of satellite parameters, earth‐station parameters and user traffic requirements, to synthesize a network architecture. The technique is particularly useful for performing high‐level trade‐offs among alternative architectures in terms of space segment requirements, the number and type of earth‐stations and overall system cost. Once the desired architecture has been selected, a detailed design may be developed

ISSN:0737-2884    

DOI:10.1002/sat.4600120304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractKey issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high‐quality service to users of BISDN via satellit

ISSN:0737-2884    

DOI:10.1002/sat.4600120305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of communication satellites as a possible way of offering broadband island interconnectivity appears to be a very attractive option, as it will enable the provision of an all‐digital, transparent service to a number of ATM islands spanning a wide area, accommodating efficiently a variety of traffic demands. The CATALYST Project (RACE II/R2074) is an attempt to demonstrate the applicability and compatibility of satellite technology with the terrestrial BISDN. In this paper we present an overview of the project and focus on an initial study of the expected user performance through the CATALYST network. Our analysis is based upon mathematical and simulation models and describes the end‐system to end‐system transfer delay for given message lengths. The protocol profiles assume a mix of Novell NetWare and Network File System client/server architectures, which are supported by either the IEEE 802.3/Ethernet or fibre distributed data interface LANs, which are themselves linked via LAN/ATM/satellite interface units. Areas of further investigation, and the implication of our analysis on the actual network architecture, are disc

ISSN:0737-2884    

DOI:10.1002/sat.4600120306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper examines the potential of satellite systems to carry synchronous digital hierarchy (SDH) transmissions and proposes a possible earth‐station architecture capitalizing on the benefits that SDH equipment offers. It is shown that a range of SDH multiplexing rates are viable over satellite and that multi‐destination operation of satellite systems is facilitated by using the inherent features of the SDH. The use of STM‐1 (155 Mbit/s) and sub‐STM‐1 transmission rates as transmission sections along with appropriate integration of the multiplexing and modem equipment would:.(a) enable SDH path continuity between earth‐stations, allowing the satellite network to be integrated with managed terrestrial networks to form global managed transmission platforms.(b) provide bandwidth and equipment savings at earth‐stations.Several technical issues relating to SDH operation over satellite systems are considered and SDH pointer corruption is examined i

ISSN:0737-2884    

DOI:10.1002/sat.4600120307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA satellite‐based TDMA network consisting of four stations within different rain climatic zones has been operated in the 20/30 GHz frequency range using a recently developed flexible TDMA system allowing for FEC code rate and transmission bit rate variation.In this paper a strategy is presented to counteract overall link degradations due to atmospheric attenuation by dynamic allocation of resources. A spare time slot within the TDMA frame as a ‘common resource’ for bit rate and code rate switching offers up to 12 dB gain, whereas up‐link power control, as it is implemented in this configuration, can cope with fades of 8 dB at maximum.For an experimental network configuration the expected long‐term performance in terms of system availability is estimated for a viable version of the resource sharing strategy. Thereby, a model to calculate the probability of concurrent attenuation at the individual earth‐station sites (‘satellite based diversity’) has been applied and the resulting probability to exhaust the resources is considered as a function of the degrading correlation between attenuations.Simulations with measured data via a ‘channel simulator’ and satellite measurements during the summer months of 1994 with the adaptive TDMA system are planned to test the functionality of the fade countermeasure strategy. Long‐term propagation measurements on large‐scale site diversity are required to verify predictions on the effective utilizat

ISSN:0737-2884    

DOI:10.1002/sat.4600120308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractMany concepts for advanced communication satellite networks have recently been proposed. Critical technical issues relating to satellite packet switching for meshed very small aperture terminal networks and broadband networks are addressed. Hardware considerations, networking and testing issues are discussed.

ISSN:0737-2884    

DOI:10.1002/sat.4600120309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ESA on‐board processing (OBP) satellite system using on‐board regeneration and baseband circuit switching has been designed to provide ISDN connectivity and services to users on a Pan‐European basis. It is thus seen at its periphery as a 2 Mb/s primary rate access, hence allowing for the interconnection of equipment and terminals compatible with this standard interface.Among the various possible network architectures that the system could support, the business‐oriented closed networks look most promising. It has therefore been retained as a prime design driver for OBP system developments. Optionally, connectivity can be offered in an optimized manner to pure data networks, e.g. for LAN‐to‐LAN interconnection at rates up to 1 Mb/s. In the paper, communication services and networking capabilities offered by the system are briefly reviewed. The internal characteristics of the satellite system allowing for such capabilities are then reviewed and the corresponding performance outlined. The system is shown to be compatible with critical CCITT performan

ISSN:0737-2884    

DOI:10.1002/sat.4600120310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractIn this paper, we study the performance of a prioritized on‐board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses both input and output buffering, switch speed‐up as well as a two‐phase head‐of‐line resolution algorithm, in order to reduce the buffer loss while maintaining acceptable user delays. The minimum required buffer capacity and switch speed‐up for each service in a prioritized environment are found underuniform traffic conditions.It is shown that under uniform traffic conditions, only minimal buffering and switch speed‐up are needed even for the lowest priority users. The performance dependence on the switch size is also substantially reduced with head of line resolution and buffering even in a prioritize

ISSN:0737-2884    

DOI:10.1002/sat.4600120311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY