J.Y. Khan

Publications (8)0.96 Total impact

• Conference Proceeding: Hierarchical ATM based LAN/MAN backbone network for a personalcommunication network

  V.W. Cheng, J.Y. Khan
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  ABSTRACT: This paper is concerned with the development of a backbone network for a high capacity personal communication network (PCN). It is expected that some of the 1st generation PCNs will be implemented on the DCS1800, which is a GSM based standard. The present backbone network of the GSM system is based on a conventional centralised structure. The paper examines the efficiency of the current GSM backbone network using circuit switched input traffic for both full rate and half rate speech coders. Finally the paper proposes an ATM LAN/MAN based backbone network which removes some of the inefficiencies of the existing GSM backbone network and can efficiently handle new services
  Vehicular Technology Conference, 1998. VTC 98. 48th IEEE; 06/1998
• Conference Proceeding: Performance of ATDMA protocol in a microcellular environment

  Yifan Li, J.Y. Khan
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  ABSTRACT: Advanced time division multiple access (ATDMA) protocol is a new generation protocol which supports both circuit switched and packet switched transmission modes. In this paper the performance of the ATDMA protocol in a microcell environment is presented. The performance of the protocol was evaluated using a proposed block reservation scheme for an integrated voice and data traffic. The effect of block reservation scheme and capture effect on the protocol performance is investigated using a discrete event simulation model
  Vehicular Technology Conference, 1998. VTC 98. 48th IEEE; 06/1998
• Conference Proceeding: Development of an integrated backbone network for a high capacity PCN network

  V.W. Cheng, J.Y. Khan, R.I. Chaplin
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  ABSTRACT: This paper describes the development of a high capacity backbone network for a personal communication network (PCN) based on a hierarchical ATM based LAN/MAN structure. It is expected that some of the first generation PCN will be implemented based on the DCS1800 architecture, which is an extended Global System for Mobile (GSM) standard. This paper discusses the features of the current GSM backbone network, which is based on a conventional centralised structure. The performance of the GSM backbone network is examined by using a simulation model. A circuit switched traffic model using the full rate and half rate speech coder specifications was used for the simulation. A hierarchical LAN/MAN structure has been proposed for an integrated backbone network which will support both circuit and packet switched traffic. The paper also discusses the implications of packet services on the existing GSM backbone network and also compares the proposed network with the General Packet Radio Services (GPRS)
  Global Telecommunications Conference, 1998. GLOBECOM 98. The Bridge to Global Integration. IEEE; 02/1998
• Conference Proceeding: Performance of packet reservation multiple access protocol in aco-channel limited mobile radio environment

  J.Y. Khan, J. Dunlop, S. Gormley
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  ABSTRACT: This paper extends the evaluation of packet protocols in a cellular mobile radio environment. Packet access protocols investigated are based on Packet Reservation Multiple Access (PRMA). The investigation was carried out for both voice and data traffic. Results were obtained by simulating a fixed channel allocation scheme based on a seven cell cluster. The authors also discuss the traffic behaviour and channel utilisation in a packet system
  Networks, 1993. International Conference on Information Engineering '93. 'Communications and Networks for the Year 2000', Proceedings of IEEE Singapore International Conference on; 10/1993
• Conference Proceeding: A packet based system for cellular digital mobile radioapplications

  J. Dunlop, J.Y. Khan, S. Gormley
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  ABSTRACT: Third generation mobile radio systems will be required to operate in a wide variety of environments from indoor picocells to outdoor macrocells. In addition the range of services accommodated will increase relative to existing systems. The implications are that a single air interface is unlikely to satisfy overall demands and that the emphasis must therefore be on flexibility. The paper examines the prospects of packet transmission to provide the necessary flexibility and draws attention to some of the issues which the implementation of packet access raise. The primary advantage of packet transmission is that bandwidth may be allocated on a demand basis. In voice communications if packet transmission is restricted to periods of voice activity this technique offers a theoretical improvement over fixed-allocation TDMA systems by a ratio in excess of 2:1, depending on the voice activity detector. Other potential advantages of packet transmission include the service independent nature of transmission (voice, video, data) and the ability to accommodate variable bit rate services
  Wireless Communications, 1992. Conference Proceedings., 1992 IEEE International Conference on Selected Topics in; 07/1992
• Conference Proceeding: A mixed voice and data protocol for digital cellular radio

  J.Y. Khan, Y. Kriaras, J. Dunlop
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  ABSTRACT: Examines several multiple access protocols to find a suitable packet transmission scheme for integrated voice and data services. The protocols which are examined are based on a TDMA frame and slot structure. Results are presented showing that PRMA (packet reservation multiple access) is a suitable option for the integrated voice and data services. This protocol provides lower speech packet loss and also lower access delay for the data traffic. For example at 1 Mb/s 40 voice connections can be supported with 120 data stations for a speech packet loss less than 1%. The HPS-DB is also an attractive option for integrated voice and data services. The main attractive feature is that different combinations of protocol can be used. For example using the HPS-DB protocol PRMA or TDMA can be used for speech packet and TM-BCMA/CD can be used for data traffic which provides lowest mean end to end delay
  Mobile Radio and Personal Communications, 1991., Sixth International Conference on; 01/1992
• Conference Proceeding: Performance evaluation of two classes of packet access for cellular radio

  J. Dunlop, Y. Kriaras, J.Y. Khan, S. Gormley
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  ABSTRACT: The suitability of packet transmission on the air interface of a cellular system is examined. Packet transmission promises to provide the flexibility required to accommodate new services and technologies with variable bit-rate requirements by allocating bandwidth on demand. An investigation is presented into the performance of two classes of packet access: time multiplex base control multiple access with collision detection (TM-BCMA/CD), which is a slotted random access technique, and packet reservation multiple access (PRMA), which is a reservation based access technique. The performance of PRMA and TM-BCMA/CD is compared with an equivalent fixed-allocation TDMA system
  Telecommunications, 1991. Third IEE Conference on; 04/1991
• Article: Performance of packet reservation multiple access for digital mobile radio using variable rate speech coder

  J. Dunlop, J.Y. Khan
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  ABSTRACT: The advantages of using adaptive bit rate voice coders to improve the performance of PRMA for digital cellular radio are considered. It is shown that such a technique forces a fairer distribution of packet loss between mobiles and is able to accommodate fluctuations in traffic levels within a cell.
  Electronics Letters 01/1991; · 0.96 Impact Factor