公开(公告)号：GB2414365B

公开(公告)日：2008-12-17

申请号：GB0411129

申请日：2004-05-19

Applicant: MOTOROLA INC

Inventor： MOLKDAR DAVOOD ,  KAPADIA MAYANK ,  WHINNETT NICHOLAS

IPC: H04B7/06

公开(公告)号：GB2414365A

公开(公告)日：2005-11-23

申请号：GB0411129

申请日：2004-05-19

Applicant: MOTOROLA INC

Inventor： MOLKDAR DAVOOD ,  KAPADIA MAYANK ,  WHINNETT NICHOLAS

IPC: H04B7/06

Abstract: A method of selecting a downlink transmit diversity technique (DTDT) from amongst a plurality of techniques for communication with a mobile station, characterised by the step of determining at least a first estimated value of a link characteristic and a radio network controller (RNC) arranged to carry out the method. The performance of a particular transmit diversity technique can be dependent on channel conditions and any additional enhancements used in the system. For example, in UMTS, the basic diversity techniques are the open loop (OL) technique and the two closed loop techniques, closed loop mode 1 (CL1) and closed loop mode 2 (CL2) and the standard enhancement is high-speed downlink packet access (HSDPA). HSDPA does not work well with the open loop technique but does work well with some closed loop techniques, e.g. CL1. In addition, the speed of mobile movement can affect a link condition and it is found that at high, medium and low speeds, the best performers are respectively, open loop(OL), closed loop mode 1 (CL1) and closed loop mode 2 (CL2). The invention thus enables the selection of the most appropriate diversity technique. In one embodiment, mobile speed can be presumed by identifying a mobility designation given to the active cells of the mobile, i.e. the mobility designation given according to the location of the cell, e.g. urban, suburban or rural. Open loop techniques include space time transmit diversity (STTD), orthogonal transmit diversity (OTD), delay diversity, time switch transmit diversity (TSTD), phase sweep transmit diversity (PSTD) and some multiple input multiple output (MIMO) techniques and closed loop techniques include selection transmit diversity (STD), transmit adaptive array (TxAA) and closed loop MIMO schemes.