DocumentCode :
1177488
Title :
On the radio capacity of TDMA and CDMA for broadband wireless packet communications
Author :
Krishnamurthy, Srikanth V. ; Acampora, Anthony S. ; Zorzi, Michele
Author_Institution :
Dept. of Comput. Sci. & Eng., Univ. of California, Riverside, CA, USA
Volume :
52
Issue :
1
fYear :
2003
fDate :
1/1/2003 12:00:00 AM
Firstpage :
60
Lastpage :
70
Abstract :
Studies of the capacity of cellular systems, stated in terms of the admissible number of remote users, have generally been limited to voice telephony. We address the problem of comparing the interference-limited performance of code-division multiple-access (CDMA) and time-division multiple-access (TDMA) systems in a packet-switched environment. The objective is to determine whether the capacity advantages claimed for circuit-switched CDMA still apply in a packet-switched environment, where the natural time diversity of bursty transmission may be a significant factor. Under a set of specific assumptions about the wireless environment (including path loss, shadow fading, multipath delay spread, cochannel interference, power control, and coding), we evaluate the number of users that can be admitted to the system while maintaining some desired quality-of-service (QoS) level. Four different classes of users with different characteristics and requirements are considered. The system capacity is found to depend significantly on the QoS objectives, which might be stated in terms of availability of some specified signal-to-interference level, packet-loss rate, or mean tolerable delay. The main finding is that strict requirements imposed on the radio access level tend to favor CDMA, whereas if some form of packet recovery is allowed at the higher layers (implying a relaxed set of requirements on the radio interface), then a somewhat higher capacity may be achieved by TDMA.
Keywords :
broadband networks; cellular radio; cochannel interference; code division multiple access; delays; encoding; fading channels; multipath channels; packet radio networks; power control; quality of service; radiofrequency interference; time division multiple access; CDMA; QoS; TDMA; broadband wireless packet communications; bursty transmission; cellular systems; cochannel interference; code-division multiple-access; coding; mean tolerable delay; multipath delay spread; packet recovery; packet-loss rate; path loss; power control; quality-of-service; radio access level; radio capacity; shadow fading; signal-to-interference level; time diversity; time-division multiple-access; voice telephony; Broadband communication; Circuits; Delay; Fading; Interchannel interference; Multiaccess communication; Multiple access interference; Telephony; Time division multiple access; Wireless communication;
fLanguage :
English
Journal_Title :
Vehicular Technology, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9545
Type :
jour
DOI :
10.1109/TVT.2002.807230
Filename :
1193091
Link To Document :
بازگشت