面向IEEE802.15.4协议的跳频信道接入方法

IEEE802.15.4协议中2.4 GHz频段的信道极易受Wi-Fi等信号干扰，且其规定节点丢失信标帧数量超过aMaxLost?Beacons 就判定为孤立节点，需要重新扫描信道进行重新同步，这必将导致较大吞吐量降低和时间消耗。本文分析IEEE802.15.4和IEEE802.11在2.4 GHz频段中信道重叠规律，提出一种利用信标帧的周期性作为跳频函数输入变量生成的跳频序列，以此快速选择未受干扰的信道，该方法不需增加信标帧负荷和开销，且简单易实现。Wi-Fi干扰源测试结果表明，平均吞吐量最低能提高约16%，平均传输延迟由25.86 ms降低到9.07 ms。

Channel Access Method of Frequency-Hopping for IEEE 802.15.4 Protocol

The channels of 2.4 GHz frequency-band of IEEE802.15.4 protocol are vulnerable to interference of Wi-Fi signals. Furthermore,a node can be sentenced as orphan node if a number of dropped Beacons is exceed to aMax?LostBeacons in IEEE802.15.4 protocol,and it re-scan all channels in order to synchronize Coordinator. So this may lead to decline the throughput and increase the time-consumption. In this paper,through analyzing overlapping dis?cipline of channels between IEEE802.15.4 with IEEE802.11,based on beacon periodicity we propose a frequency hopping function to generate the frequency-hopping sequence,which help to quickly select a communication chan?nel without interference. The proposed method is easy to implement,however,the payload and overhead of Beacon frame need not increase. The experimental results under Wi-Fi interference indicate that the average throughput may be increased by about 16%,and the average transmission delay is reduced from 25.86 ms to 9.07 ms.