The Research Of Control Channel Enhancement In LTE-A

In wireless communication systems, control channel is mainly used to transmit control information, which includes the scheduling assignment, scheduling authorization, power control commands and a series of important message; it defines the format logic of the whole communication system and means a lot to the reliability of the system. The characteristics of the fourth generation mobile communication (4th-Generation) are broadband access, distribution networks and asymmetric data transmission capacity. It is a multi-functional integrated broadband mobile communication system, known as broadband access IP system, which could provide data transfer rates of up to1Gbit/s or higher. The control channel is quite different with3rd Generation’s. Firstly, the changes of basic transmission and multiple access techniques lead to big difference in the content of signaling. On the other hand, the way of using resources of the control channel has extended to frequency division from the original code division/time division. Although a few concept of3G control channel could be used, we need to do lots of works when design the control channel of LTE system. Lots of studies focus on the enhancement of control channel.This paper mainly focuses on the control channel enhancement technique, which is consisting of Space-Time Code design, enhanced-Physical Downlink Control Channel and enhanced Inter-Cell Interference Coordination.In the first place, based on the characteristics of control signal, considering the combination of channel coding and space-time coding, we analysis the basic principle and code design criterion of BICM system. Then, a non-full spreading space-time code is proposed and the theoretical analysis dedicates that it could achieve high performance when used in control channel.Secondly, we study apply enhance-PDCCH in wireless transmition system which means PDCCH is deliverated in PDSCH region by using beamforming. The research main point is transmission location selection and we present the optimal scheme in any cases by simulation results.Finally, as both LTE and LTE-A set improvement of the performance of the cell edge users as the main demand index, the demand of same frequency heterogenous network is quite large. Unfutunately, the complex network structure leads to the competition of wireless resources between different nodes. Thus constitutes a changeable interference environment.In the heterogeneous network structure, in order to elimination the interference from the Macro cell for pico cell’s edge users, this paper studies configure "almost empty frame" in Macro cell’s downlink channel, so that the high power node and low power nodes could be time orthogonal. This paper firstly analysises the transmition strategy of eICIC scheme, and then evaluates the performance by simulation. Through the comparsion of transimition performance in different cases, we present the optimal ABS scheme.