DocumentCode :
1472521
Title :
ALOHA With Collision Resolution (ALOHA-CR): Theory and Software Defined Radio Implementation
Author :
Liu, Xin ; Kountouriotis, John ; Petropulu, Athina P. ; Dandekar, Kapil R.
Author_Institution :
Dept. of Electr. & Comput. Eng., Drexel Univ., Philadelphia, PA, USA
Volume :
58
Issue :
8
fYear :
2010
Firstpage :
4396
Lastpage :
4410
Abstract :
A new scheme, namely ALOHA with Collision Resolution (ALOHA-CR) is proposed, which is a cross-layer approach for high throughput wireless communications in a cellular uplink scenario. Transmissions occur in a time-slotted ALOHA-type fashion but with an important difference: simultaneous transmissions of two users can be successful. In the beginning of each slot, users with non-empty queues contend with some probability after experiencing an intentional random delay. If more than two users transmit in the same slot, no attempt is made by the base station (BS) to separate the collision; the packets are discarded and the users are asked to retransmit at a later time. If one or two users transmit, then, depending on the state of the channel, the base station can recover the transmitted packets. The latter is achieved by oversampling the collision signal and exploiting independent information about the users that is contained in the signal polyphase components. The properties of the user intentional random delays are determined to maximize the probability of a second order collision being separable. The throughput of ALOHA-CR under both infinite and finite backlog assumptions is derived. Under the former assumption, the optimal contention probability is calculated to maximize the system throughput, while under the latter assumption, the region of stabilizing contention probabilities is determined based on the packet arrival rate. Queuing delay analysis for network users is also conducted. The performance of ALOHA-CR is demonstrated on the Wireless Open Access Research Platform (WARP) testbed containing five software defined radio nodes. The testbed results indicate that ALOHA-CR leads to significant increase in throughput and reduction of service delays as compared to ALOHA.
Keywords :
access protocols; cellular radio; queueing theory; radio links; software radio; ALOHA-CR; base station; cellular uplink scenario; collision resolution; cross-layer approach; high throughput wireless communications; optimal contention probability; packet transmission; queuing delay analysis; signal polyphase components; software defined radio implementation; wireless open access research platform; Blind MIMO system estimation; blind source separation; collision resolution; multiuser separation; software defined radio;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2010.2048315
Filename :
5447720
Link To Document :
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