在LTE系統中，每個子載波(Sub-carrier)會因使用者所處的環境不同，產生通道衰減(Fading)，因此為了使無限資源達到最有效的利用，必須將每個子載波分配給適當的用戶，尋找一組最佳的子載波分配方案，降低所需的發射功率。 本論文針對LTE系統中下行的資源分配，來進行討論，運用PSO演算法收斂速度快，搜索範圍大且實現簡單的特點，來減少計算的複雜度，同時為了解決PSO演算法易提早收斂，陷入局部最佳解的缺點，將PSO演算法結合基因演算法中交配及突變的策略，將PSO演算法的效能進一步的提升。; In this thesis, the problem of resource allocation in downlink long term evolution (LTE) networks is investigated. To increase the spectral and power efficiency, we propose a subcarrier allocation scheme based on particle swarm optimization (PSO) algorithm. PSO can be easily implemented in discrete optimization problem and fast converge to an optimal solution, but the solution may be just a local optimum. In order to avoid trapping at local optima, the strategies of crossover and mutation are used in the proposed method. Simulation results show that the proposed algorithm can efficiently reduce the total transmission power.
