Opportunistic access in slotted aloha adapted to decentralized CSI

Research output: Contribution to conferencePaperpeer-review

6 Scopus citations


We develop a model for decentralized opportunistic transmissions of a finite (n) user slotted Aloha system that relies on decentralized channel state information (D-CSI). D-CSI refers to each user node having access only to its own uplink channel gain. Every user adapts both rate and re-transmission probability to D-CSI in every slot. Due to the variable transmission rate from slot to slot, incoming packets with fixed length are re-assembled to deliver as many bits as possible per slot. By modeling the number of bits in queues as a discrete Markov chain, we analyze the stability region and the maximum stable throughput (MST). In addition, we derive a decentralized opportunistic scheme and show that it achieves a fraction (1 - 1/n)n-1 of its centralized counterpart's throughput, where (1 -1/n)n-1 is a factor due to the inherent contention in random access.

Original languageEnglish (US)
Number of pages5
StatePublished - Dec 1 2004
EventGLOBECOM'04 - IEEE Global Telecommunications Conference - Dallas, TX, United States
Duration: Nov 29 2004Dec 3 2004


OtherGLOBECOM'04 - IEEE Global Telecommunications Conference
Country/TerritoryUnited States
CityDallas, TX


  • Adaptive Transmission
  • Decentralized Channel State Information
  • Maximum Stable Throughput
  • Multiuser Diversity
  • Slotted Aloha


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