Method and system for determining contention window change factor in adaptive backoff algorithm

Abstract

The invention is applicable to the technical field of electric communication, and provides a method and a system for determining a contention window in an adaptive backoff algorithm. The method includes the following steps: Step A: initialize the system, and initialize the value of the contention window CW to the system default value CWmin; The value of the window CW; Step C: Obtain the backoff time slot by the value of the contention window CW after updating, and obtain the channel utilization rate during this backoff time slot, and further obtain the transmission probability according to the channel utilization rate; Step D: According to the The transmission probability p determines the contention window variation factor α. The present invention obtains the optimized value of the contention window change factor by considering the addition of a new variable channel utilization rate, and dynamically adjusts it through the proportion of conflicts during backoff in the past, so that the obtained change factor is variable, and the contention window is also dynamically adjusted.

Description

technical field [0001] The invention belongs to the technical field of electric communication, and in particular relates to a method and a system for determining a contention window change factor in an adaptive backoff algorithm. Background technique [0002] In the past few decades, with the development of wireless terminal technology, distributed networks are experiencing a stage of rapid development, such as wireless local area networks (Wireless LANs), wireless ad hoc networks (Wireless ad hoc networks) and wireless mesh networks (Wireless mesh networks). Among these networks, due to its mobility, low cost, and flexibility, distributed networks have been rapidly popularized and promoted, gradually industrialized, and entered into daily life. [0003] In a wireless distributed network, the MAC (Medium access control) protocol is mainly responsible for scheduling wireless nodes and sending and receiving data, and the most widely used MAC protocol is IEEE 802.11. The IEEE...

AI Technical Summary

Problems solved by technology

[0014] The implementation of the HBAB algorithm is relatively simple, and the historical channel state is considered; however, its parameter α is allocated based on empirical values, so it cannot effectively reflect the actual channel state, and is not suitable for channels that change rapidly in real time.

[0015] In short, some traditional back-off algorithms need to dynamically adjust CW according to the estimated number of nodes. The CW obtained by such algorithms can effectively reflect the theoretical environment, but calculating the estimated number of nodes requires a lot of calculations. At the same time, if the estimation is wrong, it may affect the entire algorithm have adverse effects on

Some algorithms simply consider changing CW through linear or multiplicative rules, such as BEB and HBAB above, whose CW is simply multiplied by 2 or initialized to CW min Compared with BEB, the improvement of HBAB is that it can change CW according to the historical channel state, but its change factor α is directly assigned according to the empirical value. These two algorithms are relatively easy to implement, but they cannot effectively reflect the real-time channel environment.

Images