# Hybrid Zoning Algorithm to Optimize Overhead in Smart Mobile Communication
## 5 Zone Geographic Forwarding Rules
### First Strategy: Acting on Nodes: Z-MPR Computation  
The original MPR selection heuristic is based on the reachability of the maximum number of two-hop neighbors [29]. However, it does not take into account the MPRs layout. Selecting close MPRs lowers the network efficiency due to collision and loss of packets. To support many simultaneous broadcast transmissions without interference, our solution selects dispersive MPRs based on their reachability and their positions. When a node \(x\) computes the MPR selection, it divides the neighborhood into eight zones of equal size. Each zone forms a 45-degree angle with the axes of the system of origin \((X_{x},Y_{x})\), as shown in Figure 7(b). This choice is explained by the degree of coverage. With odd zones of 45-degree angles, if the MPR nodes are well placed, we can cover all the neighborhood of the node \(x\) and maximize the coverage of the two-hop areas as shown in Figure 7(a). With angles less than 45 degrees, the zones tend to get closer, which increases the density of MPR and the size of broadcast zones. With large angles, we find many MPRs in the same zone and it becomes difficult to elect dispersive dominant nodes because the zones cover a large part of the neighborhood of the node \(x\). The node \(x\) proceeds as follows.  
Figure 6: New OLSR message header format.  
Figure 7: Location service in OLSR.  
Start with an MPR set made of all members of \(N1\) with willingness equal to WILL_ALWAYS;
3 calculate \(D(y)\), where \(y\in N1\). \(D(y)\) is defined as the number of nodes \(u\in N1(y)\backslash\{N1,x\}\);
4. \(MPR\gets m\) if \(\exists m\in N1\), \(m\) is the only node that covers a node \(v\in N2\);
5. Remove from \(N2\) all reached nodes by \(m\);
6. remove from \(Z\) the covered zone where \(m\) is located;
7. While there are nodes in \(N2\) which are not covered by at least one node in \(MPR\); 1. Calculate \(R(w)\) for each \(w\in N1\). R(w) is the number of nodes in \(N2\) which are not yet covered by a node in \(MPR\) and are reachable through \(w\); 2. \(MPR\gets w\) if \(w\) has the highest willingness with \(R(w)\
eq 0\); 3. Remove from \(Z\) the new covered zone; 4. In case of multiple choice, \(MPR\gets u\), \(u\) has the maximum reachability. Remove from \(Z\) the new covered zones; 5. In case of multiple choice, \(MPR\gets u\), \(u\) is located in uncovered odd zone first, if not \(u\) is in an uncovered even zone with \(R(u)\
eq 0\). Remove from \(Z\) the new covered zone. 6. In case of multiple choice, \(MPR\gets y\), where \(D(y)\) is greater; Remove from \(N2\) the nodes which are now covered by nodes in \(MPR\). 7. Remove from \(Z\) the new covered zone.  
In the network presented in Figure 7(b), both nodes \(b\) and \(c\) provide the same reachability. However, node \(b\) is located in an odd zone and \(c\) is in an even zone close to the MPR \(d\). Node \(x\) will select \(b\) instead of \(c\) even if \(D(c)\) is greater. This selection will help to reduce the zone of collision in the radio channel, decrease the loss of packets and make the network more reliable.