DocumentCode :
777815
Title :
WCFQ: an opportunistic wireless scheduler with statistical fairness bounds
Author :
Liu, Yonghe ; Gruhl, Stefan ; Knightly, Edward W.
Author_Institution :
Dept. of Electr. & Comput. Eng., Rice Univ., Houston, TX, USA
Volume :
2
Issue :
5
fYear :
2003
Firstpage :
1017
Lastpage :
1028
Abstract :
We present wireless credit-based fair queuing (WCFQ), a new scheduler for wireless packet networks with provable statistical short- and long-term fairness guarantees. WCFQ exploits the fact that users contending for the wireless medium will have different "costs" of transmission depending on their current channel condition. For example, in systems with variable coding, a user with a high-quality channel can exploit its low-cost channel and transmit at a higher data rate. Similarly, a user in a code-division multiple access system with a high-quality channel can use a lower transmission power. Thus, WCFQ provides a mechanism to exploit inherent variations in channel conditions and select low-cost users in order to increase the system\´s overall performance (e.g., total throughput). However, opportunistic selection of the best user must be balanced with fairness considerations. In WCFQ, we use a credit abstraction and a general "cost function" to address these conflicting objectives. This provides system operators with the flexibility to achieve a range of performance behaviors between perfect fairness of temporal access independent of channel conditions and purely opportunistic scheduling of the best user without consideration of fairness. To quantify the system\´s fairness characteristics within this range, we develop an analytical model that provides a statistical fairness bound in terms of the cost function and the statistical properties of the channel. An extensive set of simulations indicate that the scheme is able to achieve significant throughput gains while balancing temporal fairness constraints.
Keywords :
code division multiple access; land mobile radio; multiuser channels; packet radio networks; queueing theory; statistical analysis; time division multiple access; CDMA; TDMA; WCFQ; channel conditions; code-division multiple access system; cost function; credit abstraction; downlink transmission; high-quality channel transmission power; opportunistic selection; opportunistic wireless scheduler; simulations; statistical fairness bound; statistical fairness bounds; statistical long-term fairness guarantee; statistical properties; statistical short-term fairness guarantee; temporal fairness constraints; throughput; time-division multiple access; transmission costs; uplink transmission; variable coding; wireless credit-based fair queuing; wireless packet networks; Analytical models; Base stations; Channel allocation; Cost function; Multiaccess communication; Power system modeling; Scheduling algorithm; System performance; Throughput; Wireless networks;
fLanguage :
English
Journal_Title :
Wireless Communications, IEEE Transactions on
Publisher :
ieee
ISSN :
1536-1276
Type :
jour
DOI :
10.1109/TWC.2003.816777
Filename :
1230138
Link To Document :
بازگشت