# Game Theory-Based Load-Balancing Algorithms for Small Cells Wireless Backhaul Connections +
###### Abstract  
5G wireless networks have as one of the main characteristics the large-scale deployment of small cells (microcells, picocells, etc. ), which is expected to bring several advantages in what concerns the high speed and low latency connectivity of the users. This large-scale deployment of small cells also raises several technical challenges, provisioning the backhaul connectivity being one of them. The paper considers the situations when small cells are deployed temporarily or are deployed in a vehicle transporting many passengers, situations when the traditional wired or wireless backhaul solutions could be too costly to be used. The paper proposes, as an alternative solution, the use as backhaul connections of the wireless links set up in the macro cells which cover the location of the small cell. The paper proposes several Game Theory (GT)-based Load-Balancing (LB) algorithms for distributing the traffic of the small cell users over the macro cell links. The proposed LB algorithms are evaluated by computer simulations and are compared with \"classical\" LB algorithms considered as references. The performed computer simulations show that the auction-based algorithms have the best performance in terms of delay suffered by the transmitted data packets, while the selfish routing type algorithm has weaker performance, even behaving poorly than some of the reference non-GT-based algorithms. The paper also considers the situation when several small cell APs are deployed in a limited area or a vehicle and the user groups that attach to different APs should be identified. The paper proposes two GT-based user clustering algorithms, and the performance of these algorithms are evaluated by computer simulations. These simulations show that even simple clustering algorithms could improve the distribution of the traffic over the neighbor small cell APs and reduce the delay experienced by the data packets in the transmission system. g 2023 13 1485 10.3390/app13031485 10.3390/app13031485 10.  
deployment of many small cells raises several challenges, one of them being the provisioning of backhaul connections with large data rates, low latency, and high-reliability requirements [2]. Optical fiber links, the best solution for backhaul connections in 4G and 5G networks, might be too expensive or even impossible to be deployed in a vast number of locations and, as a viable alternative, the use of wireless backhaul is proposed [2; 4]. The cost incurred by the deployment of the backhaul connections is a limiting factor of the \"network densification\" [5], having a significant influence on the number of small cells which can be deployed. In [6] it is presented a solution for optimization of the small cells' deployment process according to the type and characteristics of the backhaul connections. In some circumstances, such as small cells deployed in rural areas or small cells with low traffic or offering free access, wireless mesh networks are proposed to be used as backhaul technology, or even self-backhauling in mobile frequency bands. Due to the scarcity of the spectrum used for mobile access the last solution is useful only in particular circumstances. An analysis of the usage of mesh WiFi 802.11n networks for provisioning the backhaul connections for picocells is presented in [7], and a self-optimizing partial mesh wireless backhaul solution is proposed in [8]. The architecture of the 5G networks is a complex one organized on several functional layers and is based to a large extent on technologies such as Software Defined Networks (SDN) and network function virtualization [2; 9]. This could allow the use of more complex data transmission mechanisms, such as LB over several heterogeneous communication links. LB allows more efficient usage of the available resources in a heterogeneous networks scenario and this concept has already been extensively studied in the context of WiFi-3G/WiMAX/4G heterogeneous wireless networks.