在无状态地理转发协议中,发送节点的下一跳转发节点由当前时刻所有适合的候选节点竞争产生。候选节点在发回CTS报文竞争转发权时存在较高的冲突概率,严重影响协议性能。针对CTS冲突问题,本文提出了一种新的无状态地理转发协议,允许发送节点在RTS报文中将近期使用过的若干转发节点显式指定为首选转发节点。当RTS发出后,若存在命中的首选转发节点,则可完全避免CTS冲突,而当所有首选转发节点皆未命中时,仍可由竞争方式产生转发节点。协议中同时给出了一种高效的CTS冲突解决算法。理论分析和仿真实验证明了该协议相对于已有同类协议的优越性。
In the stateless geographic forwarding protocols, a sender's next-hop forwarder is selected based on the contention of all the suitable candidates at current time. When the candidates send back their CTS packets to contend for the forwarding right, there exists a high collision probability, which severely degrades the protocol performance. For solving the CTS collision problem, this paper proposes a new protocol which allows the sender to assign recently used forwarders as the preferred candidates in the RTS. When the RTS is sent out, if there are preferred candidates hitting, the CTS collision can be totally avoided, and if all the preferred candidates are missed, the forwarder can still be selected by the contention method. The protocol also provides an effective CTS collision resolution algorithm. Analysis and simulation prove the protocol's superiority over other existing protocols of the same class .