# An Optimal Resource Allocation Scheme with Carrier Aggregation in 5G Network under Unlicensed Band
## 1 Introduction
Therefore, we formulate the system satisfaction maximization problem based on the user satisfaction ratio of each service type to the QoS requirement with outage probability as constraint. Moreover, to flexibly modify resource allocation to each service type based on the interest of the system operator, a system-level bias is given in the problem formulation part. In the CA mode of operation, we utilize the Voronoi tessellation technique for CC allocation and primary CC (PCC) selection. Compared with the most popular two-dimensional hexagonal grid model, Voronoi tessellation is more suitable for practical cellular networks. Furthermore, aggregate characteristics of the Voronoi diagram in the Poisson-Voronoi (PV) system show superiority in analyzing networks [18]. Meanwhile, the efficient utilization of limited resources has been a major issue in wireless communication systems. In [19], a new dynamic CA scheduling scheme to improve the energy efficiency of uplink communications is proposed. In [20], carrier price per unit bandwidth is used to allocate multiple carrier resources optimally among users in their coverage area while giving the user the ability to select one of the carriers to be the primary carrier and the rest to be secondary carriers. Nevertheless, the integration of 5G-U and CA technology issues a challenge to existing networks, which cannot be addressed by the currently proposed schemes. In [12; 21], Q-learning and double Q-learning methods are used for carrier selection and discontinuous transmission under efficient coexistence of 5G and Wi-Fi in unlicensed spectrum bands. However, existing studies represented by [12; 21] did not consider multiple types of services in LTE-Advanced (LTE-A), which has already been one of the most fundamental and important network environments. In this paper, we propose an optimal resource allocation mechanism to maximize system satisfaction under the constraints of variable QoS requirements for multiple types of services and outage probability thresholds in 5G-U networks with a CA feature. Firstly,PCC and secondary CC (SCC) are selected optimally among all the aggregated CCs for different service types based on carrier quality and service type characteristics. Secondly, the outage probability for each service type is derived. Thirdly, the reserved unlicensed spectrum for rate-sensitive service is minimized to satisfy QoS requirement. Fourthly, mean packet transmission delay for delay-sensitive service is analyzed by the M/G/1 queue modeled in the corresponding user equipment (UE). Lastly, system satisfaction utility function is formulated and maximized with variable QoS requirements satisfied for different service types. Moreover, to flexibly modify resource allocation to each service type based on the interest of the system operator, a system-level bias is given in the problem formulation part. The numerical results reveal the superior effectiveness of the proposed scheme. The main contributions of this paper are listed as follows: 1: The RB resource allocation problem is turned into an UE aggregation problem for each CC and is then solved by utilizing the Voronoi tessellation properties. 2: The reserved unlicensed spectrum minimization problem is formulated and solved to protect the unlicensed band UE. 3: The mean packet transmission delay is derived for the delay-sensitive UE. 4: A system satisfaction maximization problem is formulated to take variable QoS requirements into one evaluation system and be maximized by optimally allocating spectrum and power resources. The notations in this paper are specified in Table 1.