# Fuzzy Logic-Based Geographic Routing Protocol for Dynamic Wireless Sensor Networks
## 1 Introduction  
As a novel information acquisition and processing mode, the wireless sensor network [1; 2] collects information through a large number of sensor nodes distributed within a monitored area and then provides it to users after processing. Due to the limited communication distance between sensor nodes, information transmission needs to be completed by multi-hops. Therefore, a routing technology with low routing overhead and high reliability has become the key technology used for wireless sensor networks.  
Geographic routing can establish routing by using only the location information of local nodes. Specifically, it can directionally forward information to a destination node without flooding the information in the entire network. Hence, geographic routing is considered very efficient in multi-hop wireless sensor networks.  
For existing geographic routing protocol, it is generally assumed that nodes can obtain their own positions through location services [3] or a global position system (GPS) [4], and the location of a destination node can be acquired through a location service algorithm, such as the grid location service (GLS) [5].  
However, with the application expansion of wireless sensor networks, the movement of sensor nodes will occur in some scenarios, such as aviation sensor networks. For dynamic wireless sensor networks, the existing routing protocols, based on location service algorithms, incur an additional routing overhead and storage overhead. In addition, the obtained node location is not accurate enough, resulting in routing failure. Consequently, the high routing overhead problem and inaccuracy location problem also occur in existing geographic routing protocols.  
In addition, the routing void problem and network planarization problem [6] also occur for the main component of geographic routing (the greedy forwarding mode and perimeter forwarding mode [7]), resulting in a longer path with a higher overhead.  
This paper proposes a fuzzy logic-based [8; 9] geographic routing protocol (FLGR) through researching the geographic routing protocol without the real-time location information of the destination node, and aims at solving the aforementioned problems. In particular, the main contributions of this paper are as follows:  
* A novel data forward mode is proposed based on the fuzzy location region of the destination node.
* Aiming for fewer hops and a higher packet delivery rate, the selection criteria and parameters for assessment are also proposed.
* In addition, to avoid the routing void problem, the routing void avoidance scheme is proposed to reduce the rate of routing failure by adjusting the candidate node region (CNR) and discarding the void node.
* Based on the fuzzy logic system, subordinating degree functions, the fuzzy reasoning rule, and the defuzzification method are proposed.
* The feasibility of the FLGR forwarding mode is verified through MATLAB simulation. The performances between FLGR protocol and existing protocols are compared by simulation using the QualNet platform.  
The rest of the paper is organized as follows: Section 2 presents previous works on this topic. Section 3 describes the details of the FLGR protocol. The feasibility verification of the FLGR forwarding mode and the performance comparison between FLGR protocol and others are presented in Section 4, followed by conclusions in Section 5.