在LTE/LTE-A網路上研發適用多細胞多天線及單播群播串流之具有服務品質保證的高效省電排程方法

Abstract

3GPP LTE-A (Long Term Evolution-Advanced，長期演進技術)是目前最受推崇的4G無線通訊標準之一，其支援正交分頻多工、多天線傳輸及多細胞協同傳輸等新技術，使傳輸頻寬提升至1Gbps並豐富了媒體服務的多樣性。為了確保媒體串流之服務品質，3GPP LTE-A嚴格定義多項服務品質類別，並具體規範服務型態及參數限制。同時，LTE-A標準也制訂了Discontinuous Reception Mechanism (DRX)之省電機制，使行動裝置在空閒時能關閉無線介面以進入睡眠狀態，達成節能。然而，如何有效安排多細胞多天線的傳輸，同時最佳化DRX機制仍是一個開放的問題。有鑑於此，本計劃主要針對最常見的單播及群播串流來作考量，設計兼顧省電及串流服務品質保證的方法，並適用於低運算能力的行動裝置上。 本計畫分三年執行；第一年我們研究3GPP LTE-A多細胞多天線下的傳輸機制管理；第二年我們深入探討單一細胞下的省電機制及資源排程，設計適用於單播串流的高效能省電排程方法；第三年我們將延伸前兩年的成果，擴大探討群播串流的服務品質，並設計適用的省電排程協定。本計畫研究的傳輸協定控制及睡眠排程演算法會同時考慮固定位元速率及變動位元速率的即時性串流和非即時性串流，我們將藉由效能分析和模擬評估所提出的方案及協定以達到最佳的效能，成果預期將對行動通訊系統產生重大的進展。

The 3GPP LTE-A (Long Term Evolution-Advanced) is the most promising technology for next-generation wireless communications. It supports OFDMA (orthogonal frequency division multiple access), Multi-Antenna, and Multi-Cell based CoMP (coordinated multipoint) techniques which significantly improve the transmission rate and enrich the types of multimedia services. To ensure the QoS (quality of service) of multimedia services, 3GPP LTE-A has defined multiple QoS classes to specify the service types and their requirements. In addition, to save energy of UEs (user equipments), the LTE-A standard also defined the discontinuous reception (DRX) mechanism to allow UEs turning off their radio interfaces to save energy when they are idle. However, how to schedule the transmission techniques and optimize DRX configurations for UEs are still left as open issues. In this project, we consider the unicast and multicast services of UEs and design a suit of scheduling schemes to guarantee the QoS of streams while minimize the consumed energy of UEs, especially for those low computing-power ones. This project aims to propose a three-year research work. In the first year, we will study the transmission scheduling problem in the multi-cell and multi-antenna based 3GPP LTE-A network. In the second year, we will deeply focus on the single-cell LTE-A network and design a sleep scheduling mechanism for UEs with unicast streams. In the third year, we will extend the results of the previous two years and design an enhanced sleep scheduling mechanism for UEs with multicast streams in the LTE-A network. In these protocols and mechanisms, we will consider constant/variable bit-rate and real-time/non-real-time traffic. All of the proposed mechanisms will be evaluated by mathematical analyses and simulations. With these evaluations, our mechanisms can be further improved to achieve more excellent performance. We expect that the results of this project would provide valuable information for the future system design of mobile communications.