# On the Optimisation of Practical Wireless Indoor and Outdoor Microcells Subject to QoS Constraints
## 2 Related Works  
Network planning and optimisation are vital design requirements in practical cellular networks, especially when the number of mobile devices is dramatically increasing along with cell sites of different sizes and capacity. It is particularly crucial to consider various factors of communication environment in the network planning [35; 36; 37; 38; 39]. Specifically, in [35], an optimisation framework for selection and configuration of base stations were proposed based on simulated annealing algorithm. The finding of optimal position for base stations was also investigated in [36] where different optimisation problems were formulated as integer linear programs with respect to different objectives and constraints. Similarly, the simulated annealing was exploited in [36] as an approximate technique for solving the large-scale combinatorial optimisation problems. In [37], a greedy algorithm was proposed to select and configure base station locations given the candidate sites and multiple-objective genetic algorithms were exploited to find an optimal ordering of the potential base stations. Considering 3G cellular networks, the network planning was investigated in [38] where mixed-integer programming models were developed to determine where to install new base stations and how to select their configuration such as antenna height and tilt, pilot signal, maximum emission power, sector orientation, etc. Since the integer programming is non-deterministic polynomial-time (NP)-hard,a Tabu Search algorithm was adapted to provide approximate solutions with a lower computation complexity [38]. In [39], a combinatorial approach for optimising the location of the base stations was developed for the 4G systems with mixed cells and MIMO techniques. There exist a number of approaches for radio planning using various simulation software programs, such as Actix Analyzer [41], Wireless InSite [42], WinProp [43], ComStudy [44], Broadband-eQ [45], Planet [46], deciBel Planner [47], WaveSight [48], EDX SignalPro [40], etc. Specifically, Actix Analyzer [41] is one of the leading industry desktop solutions for radio frequency planning and optimisation, providing great visualization capabilities that enable engineers to analyze complex data in an effective and intuitive way for indoor and cellular networks. Exploiting ray-tracing models and high-fidelity solvers, Wireless InSite was developed in [42] for planning and optimisation of radio frequency. The Wireless InSite was shown to obtain accurate and efficient predictions of electromagnetic propagation and communication channel characteristics in complex urban, indoor, rural and mixed path environments. Some of its applications include predicting coverage, determining shadowing and multipath effect, assessing wireless backhaul solution and evaluating channel characteristic of various network models, e.g., 4G Long Term Evolution (LTE), LTE-Advanced, 5G [49] and indoor WiFi, with evolved techniques, e.g., MIMO and massive MIMO. Another software program, namely WinProp [43], was created to provide high accurate and fast analysis of the wireless propagation with applications ranged from rural to urban, from indoor to outdoor, from satellite to terrestrial, etc. Along with the above professional software, a simple software named ComStudy [44] was designed by Radio soft company as a complete and easy-to-use solution for all radio engineering and spectrum needs; however, it is not powerful for design engineers to cope with practical network design issues. Dealing with sophisticated radio propagation modeling for voice and data, Broadband-eQ was developed in [45] for network optimisation and management. The Broadband-eQ also allows us to evaluate the coverage and capacity, mitigate interference, analyse grade of service and throughput, with automated frequency allocation towards next generation technologies. With the requirement of live mobile network planning, Planet was built in [46] and has been used by many mobile network operators.