Method for multiple time slot power control

#The invention relates generally to the power control technique of a CDMA mobile communication system, and more particularly to the power control method of a multiple time-slot power control pattern.

#Power control is an important technique for a CDMA mobile communication system. Purpose of the power control is to overcome near-far effect in the way that a system not only keeps higher communication quality, but also operates without interference to other subscribers sharing the same channel. In the 3G mobile communication system, the power control uses decision feedback mode, which works as follows. The receiving end B measures signal-to-interference ratio (SIR) of a received signal, then, the measured SIR value is compared with a SIR threshold-value to generate a Transmit Power Control (TPC) command. The TPC is sent to the transmitting end A, and A adjusts the transmitting power based on the received TPC command. Usually, the adjustment happens once for a time-slot.

#In a wideband CDMA (WCDMA) system, a multiple time-slot TPC control method has been defined (reference to 3GPP TS25.211). In this method, the receiving end B also sends back a TPC command to the transmitting end A during every time-slot. However, during every N time-slot, from the 1st to the (N−1)th, the transmitting end A does not adjust the transmitting power with the TPC command, but at the Nth time-slot, the transmitting end A adjusts the transmitting power based on the N TPC commands. In this case, the N time-slots are seen as a power control group. The specific procedure is as the following:

#FIG. 1 shows a flowchart of TPC command transmitted in the receiving end.

#The invention will be described in more detail, hereinafter, with reference to the drawing.

#The invention replaces the all “1” or all “0” TPC command with an encoded symbol. In the transmitting end A and the receiving end B, two encoded symbols are pre-stored, respectively. The encoded symbols can be generated as follow: suppose length of every time-slot TPC command is k bits, then (N×k, k) encoding is made; the encoding information elements are only two kinds: k “1” bits or k “0” bits; encoded symbol 1 with N×k length corresponds to the all “1” TPC command, and encoded symbol 2 corresponds to the all “0” TPC command. In addition, there is a mark register set in the receiving end.

#TPC command transmitting flow, at the receiving end B, is shown in FIG. 1. (1) When the receiving end B generates the first TPC command, an unencoded TPC command generated currently is sent to the transmitting end A. (2) Starting from the second time-slot, the receiving end executes the following procedures: