| HSPA+ is the evolution based on HSPA, it retains some key technologies of HSPA, such as fast scheduling, Hybrid ARQ & soft combining, downlink short frame of 2ms, uplink frame of 10ms/2ms, adaptive modulation and coding, etc. HSPA+ also retains all channels of HSDPA/HSUPA, such as HS-PDSCH, HS-SCCH, HS-DPCCH, E-DPCCH, E-DPDCH, E-RGCH, E-AGCH, E-HICH, F-DPCH, etc.As a result, it is totally compatible with HSPA. However, there are some new technologies in HSPA+ system to support more services and higher data speed, and MIMO is the most important one of them.The current researches on MIMO application are focused on multi-antenna. Actually, multi-antenna in MIMO system brought many improvements and perhaps problems. Lots of researches such as per-antenna-rate-control and per-antenna-power-control have been made to solve these problems. However, co-channel interference (CCI) introduced by the transmitting antennas of MIMO base station has never been solved in the past researches, some researchers even ignored it. In an experiment, some individual antennas were excluded by power distributing system in MAC layer, system throughput unexpectedly increased; this phenomenon provided a very precious subject in HSPA+ application field. Actually, technology of per-antenna-power-control can more or less eliminate CCI, but its core idea is to allocate more transmitting power to better channels to pursue better throughput. In practical systems, average method is still used in power distributing, because the water-filling algorithm is very complex and the improving methods are still too complex or losing too much throughput.The 4×2 structure, i.e. 4 transmitting antennas at BS and 2 receiving ones at UE is used by most of the current MIMO systems. This article mainly researches on 8×2 MIMO system, and there are real equipments and platform to support the improving researches on physical layer and MAC layer algorithm. A new idea of adaptive single-dual-stream (SDS) algorithm based on dynamic antenna-choice was proposed in this article. Firstly, antenna-choice method based on iterative algorithm is put forward, and then, an adaptive SDS algorithm is proposed basing the antenna-choice method. At last, simulation result by TD-HSPA+ system simulating platform is given to prove the effect of the new algorithms.Basing on the previous researches, the application field of channel capacity is studied further in this article. Phase-control-antenna (PCA) is introduced to MIMO system, a new SHPCA multi-antenna system is put forward to improve system capacity, and a three dimension channel capacity formula is invented based on Shannon formula. Furthermore, antenna-choice method is integrated into SHPCA system to design a new adaptive SDS algorithm for it, and simulation result is given to prove the huge effect of 70 Mbps throughput by SHPCA. Improving of channel capacity and simulation result of MIMO system with SHPCA technology are both given in this article.Because HSPA+ is a transition technology between HSPA and LTE, the relationship between HSPA+ and LTE is described in the end of this article, and the network scheme is discussed too. |
