| Since the 21 st century, the emergence of new technology represented by OFDM technology accelerated the development of wireless communication technology. With the development of wireless communication technology, the network service becomes more and more diversified and the amount of wireless data is growing rapidly, which makes the limited spectrum resources face a great challenge-how to use the limited spectrum resources to provide multimedia services of satisfactory quality for users and ensure the fairness among users. This requires wireless scheduling algorithm to allocate wireless resource efficiently and reasonably, on the other hand, the waste of spectrum resources should be minimized. International organization 3GPP started the LTE standardization work in 2005. However the packet scheduling algorithms have not been clearly defined in the LTE criterion. So in this paper, the downlink scheduling algorithm in LTE is investigated.The thesis is organized as follows. Firstly, this paper gives a brief introduction of the history of cellular mobile communication, LTE network architecture and key technologies. The evaluation criteria and the key challenges of wireless packet scheduling algorithms are described subsequently. What’s more, we study several existed scheduling algorithms and compare their performance characteristics and application limitations. Finally, a packet scheduling algorithm for the mixed business scenarios is designed is this paper. The users’ delay, channel information and the users’ demand for the high quality of service are taken into account in the scheduling algorithm and we evaluates the necessity of packet transmission according to the users’ feedback of channel quality, which can avoid the waste of resources. The results of simulation show that the average packet delay and packet loss rate of real-time service, e.g., video and Vo IP is reduced in the algorithm we proposed. Further more, the fairness among users is improved in the designed algorithm. |
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