Abstract:
To address the issue that the multi-hop bandwidth of existing wireless Mesh networks cannot support real-time, high-throughput services such as audio and video in mines, the intra-flow contention mechanism of multi-hop paths in mine wireless Mesh networks was analyzed, revealing the mechanism of multi-hop bandwidth degradation. It was pointed out that multi-hop relay systems with more than six hops have an optimal convergence ratio, which can potentially constrain the 1/
n (
n being the number of links) bandwidth degradation trend. However, systems with six or fewer hops cannot constrain this trend. The key factor determining the existence of an optimal convergence ratio is the ratio
ΔS between the carrier sensing distance and the stable communication distance. When path nodes are uniformly distributed with
ΔS=2, the optimal convergence ratio is 1/6. Due to the unique boundary characteristics of wireless transmission in mines,
ΔS≈3, resulting in an optimal convergence ratio of 1/8 when nodes are uniformly distributed. However, the asymmetric and unstable nature of wireless coverage in mines prevents uniform node distribution. Therefore, for a 10-hop path in a simulated mine, the optimal convergence ratio is 1/5. Based on the idea of constraining the contention range, a method of constructing a chain network using frequency-division segmented serial hybrid links was proposed. Without modifying the Mesh protocol, this method constrained intra-flow contention within each path segment by splitting the path using different frequencies. Experimental results showed that when the number of wireless links exceeded ten hops, the bandwidth between the first and last nodes in the chain network was greater than the multi-hop bandwidth of traditional Mesh paths, and the convergence ratio also exceeded 1/
n, validating the feasibility of the proposed method in constraining the 1/
n bandwidth degradation trend.