  Congestions in wireless sensor networks (WSNs) could potentially cause packet
loss, throughput impairment and energy waste. To address this issue, a
hop-by-hop cross-layer congestion control scheme (HCCC) built on
contention-based MAC protocol is proposed in this paper. According to MAC-layer
channel information including buffer occupancy ratio and congestion degree of
local node, HCCC dynamically adjusts channel access priority in MAC layer and
data transmission rate of the node to tackle the problem of congestion.
Simulations have been conducted to compare HCCC against closely-related
existing schemes. The results show that HCCC exhibits considerable superiority
in terms of packets loss ratio, throughput and energy efficiency.
