Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

Telemetry downlink interfaces and level-zero processing

The technical areas being investigated are as follows: (1) processing of space to ground data frames; (2) parallel architecture performance studies; and (3) parallel programming techniques. Additionally, the University administrative details and the technical liaison between New Mexico State University and Goddard Space Flight Center are addressed

Improving Channel Throughput of WLANs and Ad Hoc Networks Using Explicit Denial of Requests

A new Multiple Access Control scheme for wireless ad hoc networks and WLANs is proposed. This scheme uses explicit denial of channel requests and a busy tone to improve channel throughput. Performance analysis shows significant improvement when the network is under heavy traffic load

Enhancement Of Transmission Control Protocol Performance Over Low Earth Orbit Satellite Links

Recent growth of the Internet has led to the development of Internet services everywhere and over every possible communications medium. Here, Low Earth Orbit (LEO) Satellite has been addressed as a medium for supporting services based on the Transmission Control Protocol (TCP). Basically, TCP was proposed as a common transport protocol for the Internet. The TCP mechanisms have been modified overtime and almost standardized for wired networks. However, for wireless communications still further modifications are needed for TCP mechanisms. Particularly, in this study an Enhanced Selective Acknowledgement (ESACK) mechanism has been proposed to improve the performance of TCP over LEO satellite links. The ESACK detects the network congestion and adjusts the transmission window by considering losses in two consecutive windows

An adaptive ISMA-DS/CDMA MAC protocol for third-generation mobile communications systems

In this paper, an inhibit sense multiple access–direct sequence/code division multiple access (ISMA-DS/CDMA) medium access control protocol for a packet transmission mobile radio network is presented. The main feature of this protocol is its ability to retain the inherent flexibility of random access protocols while at the same time reducing to some extent the randomness in the access in order to increase the system capacity. In this framework, the protocol is presented together with some adaptive mechanisms that improve the protocol performance by means of regulating the access and varying the transmission bit rate according to the channel load that is broadcast by the base station. As a result, an adaptive bit rate algorithm is presented that reaches a throughput value close to the theoretical maximum.Peer Reviewe

A packet radio system for an industrial data network.

Thesis (M.Sc.Eng.)-University of Natal, 1992.This project was undertaken for a commercial electronics company, CONTROL LOGIC (CONLOG) which is involved in the research, design, development and manufacture of data acquisition, control, energy management and automotive equipment. Currently CONLOG uses an inhouse token passing local area network CONET for industrial data communications.The need had arisen to provide a means of data communication amongst widely geographically distributed remote terminal units (RTUs) generating demands at a very low duty cycle. A need for communications between RTUs and a centralised controller was also required. In addition to this, multihop communications between the RTUs was required. Packet switching using a broadcast radio network provides an efficient means of achieving this. An investigation into to the various media access control protocols and contention techniques using packet radio was carried out. The various media access techniques were compared with respect to throughput and normalised delay. This led to the selection of a media access scheme for the packet radio network using RTUs. A protocol specification control is centralised or Interconnect Organisation.The switching protocol (OSI) for the packet radio network, in which distributed, was done. The architechure of specified adheres to the Open Systems model of the International Standards.An experimental packet switching radio network was implemented using the protocol specification defined above. The packet radio network (PACNET) uses existing off the shelf radios and purpose built hardware for the remote terminal units. The thesis describes methods of data communications suitable for widely dispersed industrial data communications, the selection of the packet switching media access methods and control protocols, and the design and implementation of the prototype system

Application of advanced on-board processing concepts to future satellite communications systems

An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development