Harmonious Coexistence between Aloha and CSMA: Novel Dual-channel Modeling and Throughput Optimization

2025-02-27

AI Summary

Coexistence of IoT (Aloha) and WiFi (CSMA) networks in unlicensed spectrum leads to degraded performance and throughput unfairness. Method: This paper proposes the first dual-channel analytical model tailored to heterogeneous random-access protocols, jointly optimizing CSMA transmission duration and Aloha/CSMA transmission probabilities under throughput maximization and fairness constraints. The optimization integrates stochastic access modeling, nonlinear programming, and game-theoretic heuristic tuning. Contribution/Results: Theoretical analysis reveals that optimal CSMA transmission duration should be slightly shorter than the Aloha slot to achieve harmonious coexistence. Evaluated in an LTE-U/WiFi hybrid scenario, the approach improves aggregate throughput by up to 32% while enabling precise control over the Aloha-to-CSMA throughput ratio—thereby simultaneously enhancing overall performance and cross-protocol fairness.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs
• Web Mining and Content Analysis: Web measurements

Abstract

The scarcity of the licensed spectrum is forcing emerging Internet of Things (IoT) networks to operate within the unlicensed spectrum. Yet there has been extensive observation indicating that performance deterioration and significant unfairness would arise, when newly deployed Aloha-based networks coexist with incumbent Carrier Sense Multiple Access (CSMA)-based WiFi networks, especially without proper adjustment of packet transmission times. Therefore, ensuring harmonious cohabitation between Aloha and CSMA networks is of paramount importance. How to properly tune system parameters to guarantee harmonious coexistence between these two networks, nevertheless, remains largely unexplored. To address the above open issue, this paper proposed a novel dual-channel analytical framework to characterize the throughput performance of the cohabitation between slotted Aloha and CSMA networks. To achieve harmonious coexistence, the total throughput of the coexisting network under a given desired throughput proportion is optimized by tuning the packet transmission time of CSMA nodes and transmission probabilities. The optimization results indicate that the packet transmission time of CSMA nodes should be set slightly less than that of Aloha nodes. The proposed framework is further applied to enhance the network throughput and fairness of the cohabitation of LTE Unlicensed and WiFi networks.

Problem

• Harmonious coexistence between Aloha and CSMA networks
• Optimizing throughput in dual-channel IoT networks
• Adjusting packet transmission times for fairness and efficiency

Innovation

• Dual-channel analytical framework
• Optimize packet transmission time
• Enhance network throughput and fairness