# Hybrid Zoning Algorithm to Optimize Overhead in Smart Mobile Communication
## 1 Introduction  
In the last few years, several studies have been carried out with the aim of miniaturizing computer technology, which gave rise to the Internet of things [1]. The ubiquitous objects provide many daily tasks to make human life easier by sensing the environment and applying knowledge [2]. They affect many domains including wireless sensors [3], mobile ad hoc networks [4], smart cities, unmanned airplanes, smart transport, and smart homes, to name a few [5]. The smart objects need to interact with each other to exchange information about their environment or to communicate with the cloud [6]. Due to various applications of smart environment, different communication technologies and hardware systems must coexist together. These networks vary in size and area covered, and need precision for more security, especially in delay-sensitive environment where the probability of collision increases [7]. The network latency and the packet loss are the main factors that affect the delay [8].  
The routing protocols in smart environment have to deal with the lack of resources in smart devices [9]. The proactive mobile ad hoc network (MANET) protocols, such as the optimized link state routing protocol (OLSR) [10] where the routes are already calculated, help to reduce the response time of devices. However, each node has something to say every couple of seconds. With high density of nodes in a shared space, the packet loss and the network latency increase drastically [11]. The OLSR adopted the Multipoint Relays (MPR) concept to reduce the overhead related to the protocol. However, the MPR concept suffers from broadcast redundancies and collision in the radio channel, especially at the level of MPR nodes. Many studies have been conducted to reduce the cost of overhead inOLSR [12, 13]. Some solutions have made changes to the MPR computation in order to select different MPR based on metrics such as velocity, energy, location, signal range, etc. Other solutions focus on the transmission of messages, especially the broadcast transmissions.  
In this paper, we use a combination of two zoning techniques to decrease the cost of the routing protocol overhead and to ensure better quality of service (QoS) [14]. Our solution acts locally based on one-hop neighbor information in order to select dispersive dominant nodes to decrease the collision at the level of MPRs. The second method acts globally on the entire network. It divides the network into multiple propagation zones and it avoids useless transmissions between nodes of different zones. In previous work, we proposed the Zone Multipoint Relays (Z-MPR) [15], an improved algorithm that optimizes the MPR computation in OLSR. In another work, we proposed a zoning technique to avoid the useless transmission of topology control (TC) messages that gave birth to the Geographic Forwarding Rules (GFR) [16]. In this paper, we propose a solution that combines the two techniques within the same algorithm called Zone Geographic Forwarding Rules (Z-GFR). The local zoning technique and the overall zoning technique are different. However, both techniques coexist and operate in the same routing algorithm in a distributed manner. The Z-GFR reduces the number of transmissions of topology control messages while it assumes good propagation of the topology and ensures better QoS [17] for applications.  
The remainder of the current paper is organized as follows: Section 2 summarizes some hybrid techniques that aim to reduce the overhead in mobile ad hoc network. Section 3 describes the problem formulation and discusses our proposed solution. In Section 4, we present the modeling of the OLSR protocol. Section 5 details the hybrid solution zone geographic forwarding rules in the context of OLSR protocol. The first strategy is presented in Section 5.2, while Section 5.3 details the second strategy. The performance of the proposed algorithm is presented via simulations in Section 6. Finally, Section 7 concludes the paper.