# Game theory-based Routing for Wireless Sensor Networks: A Comparative Survey
## 3 Game Theory-Based Routing Protocols in WSNs
### Routing Protocols Based on Noncooperative Games
#### 3.2.3 Routing Framework based in the Energy and Delay Conservation  
To determine optimal routing paths using signal-to-interference and noise ratio (SINR), [PERSON] et al. designed a game theory-based routing protocol in [37] for WSNs. The game was modeled to be a noncooperative, dynamic, and incomplete information game. The sensor nodes were assumed to be static and they acted as players in the designed game. The utility function was formulated to facilitate a balance between delay and energy consumption. The authors of [37] demonstrated that the Nash equilibrium was self-imposed if the players played their best response strategy.  
The designed routing game in [37] considered the SINR and channel capacity between two communicating nodes. The objective of this routing scheme was to find out a route that could jointly decrease the energy consumption and delay. The formulated game precipitated the system to achieve Nash equilibrium. Owing to this, all the nodes in the network could optimally utilize its energy and increase its lifetime. The network considered consisted of randomly deployed nodes. The nodes were homogeneous in nature. The maximum amount of interference was infinite in amount. The nodes in the network acted as players in the game, as mentioned earlier, and could choose a strategy depending on the utility function. The selection of a node as a next hop depended on the congestion at that node.  
The designed game in [37] consisted of \(N\) players (sensor nodes), where \(N=\)\(i_{1}  
where \(E\) is the initial energy of the nodes, \(D_{ref}\) is the reference delay in the network, \(Delay\) is the routing path delay, \(E_{ref}\) is the reference energy in the network. The net utility of the game was given by:  
\[U_{net}(S_{i},S_{-i})=\frac{LR}{Mp_{i}}+f(\gamma_{i})-\frac{E}{E_{ref}}+\frac{ Delay}{D_{ref}}. \tag{21}\]  
For each stage of the game, the net utility was calculated for all neighboring nodes and the node that maximized the net utility.  
According to the performance study in [37], the delivery latency was improved in the designed protocol, and its energy consumption was considerably less than that of the destination-sequenced distance vector routing [1], AODV [55], and DSR [1]. This protocol claimed to outperform the two very popular routing protocols of AODV and DSR in terms of energy efficiency only. The simultaneous transmission of all the nodes can easily lead to network congestion in this protocol.  
Technical strengths:  
* The protocol can successfully decrease network delay to a significant amount;
* Energy consumption was successfully decreased to a fair amount. Technical weaknesses:
* The authors did not consider sufficient routing metrics in the performance comparison. A performance comparison graph on network lifetime was necessary to prove the robustness of the protocol with the compared ones.  
Applications:
* Applicable where an application requires continuous data delivery without any delay. Probable future improvement:
* The authors claimed that the Nash equilibrium was self-imposed. They did not provide sufficient proof to support their claim.