Performance of UMTS packet service over dedicated channels (DCH)

The provision of high speed packet data services in an efficient way is probably the most important challenge for UNITS since this can give an advantage with respect to second generation systems. The efficiency mainly depends on the radio interface and since it is characterized by a great flexibility it is of utmost importance to investigate the effect of different configurations on the system performance. In this paper we evaluate the performance of packet data services over downlink dedicated channels (DCH) by means of detailed simulations. Due to the traffic variability, ARQ mechanism and dosed loop power control the system behavior is quite complex and not so easily predictable as with constant rate services such as voice. We study the effect of several parameters (spreading factor, code rate, channel setup delay, etc.) on the system capacity by means of the delay-throughput curves. We show that the setting of parameters may be critical for system capacity and stability. For this reason we propose a flow control mechanism which is able to guarantee stability and to make the system capacity almost independent of channel rates.

[1]  Wayne E. Stark,et al.  Channels with block interference , 1984, IEEE Trans. Inf. Theory.

[2]  Flaminio Borgonovo,et al.  Packet service in UMTS: delay-throughput performance of the downlink shared channel , 2002, Comput. Networks.

[3]  Michael Meyer,et al.  Wireless Internet access based on GPRS , 2000, IEEE Wirel. Commun..

[4]  Flaminio Borgonovo,et al.  Retransmissions versus FEC plus interleaving for real-time applications: a comparison between CDPA and MC-TDMA cellular systems , 1999, IEEE J. Sel. Areas Commun..

[5]  Antonio Capone,et al.  Performance of UMTS Packet Service over Dedicated Channels (DCH) , 2003, Int. J. Wirel. Opt. Commun..

[6]  Joseph Y. N. Hui,et al.  Throughput analysis for code division multiple accessing of the spread spectrum channel , 1984, IEEE Transactions on Vehicular Technology.

[7]  Krzysztof Pawlikowski,et al.  On credibility of simulation studies of telecommunication networks , 2002, IEEE Commun. Mag..

[8]  Andrew J. Viterbi,et al.  Erlang Capacity of a Power Controlled CDMA System , 1993, IEEE J. Sel. Areas Commun..

[9]  A. Samukic,et al.  UMTS Universal Mobile Telecommunications System: development of standards for the third generation , 1998, IEEE GLOBECOM 1998 (Cat. NO. 98CH36250).

[10]  W. Mohr,et al.  Research activities on UMTS radio interface, network architectures, and planning , 1998, IEEE Commun. Mag..

[11]  Antti Toskala,et al.  Wcdma for Umts , 2002 .

[12]  V. Rich Personal communication , 1989, Nature.

[13]  Donal O'Mahony UMTS: The Fusion of Fixed and Mobile Networking , 1998, IEEE Internet Comput..

[14]  Ramjee Prasad,et al.  An overview of air interface multiple access for IMT-2000/UMTS , 1998, IEEE Commun. Mag..

[15]  L. B. Milstein,et al.  Performance of closed-loop power control in DS-CDMA cellular systems , 1998 .

[16]  M. Gallagher,et al.  UMTS the next generation of mobile radio , 1999 .