CN1210978C - Power control method under base station selected diversity transmission - Google Patents

Abstract

The invention discloses a power control method for base station selection diversity transmission. The downlink transmission power includes two levels of P1 and P2. Processing; wherein: when the UE uses the PDSCH channel of the cell in the active set, the power of TPC is set to 0, and the power of TFCI and PILOT is set to P1+PO1 and P1+PO3 respectively; when the UE user equipment does not use the cell in the active set In PDSCH channel, the power of TPC, TFCI and PILOT are all set to 0. If the UE does not use the PDSCH channel of any cell in the active set, the non-primary cell can turn off its DPDCH output and DPCCH output; if the UE uses the PDSCH channel of a cell in the active set, when the cell is a non-primary cell, the cell can Close its DPDCH output and TPC output of DPCCH. Therefore, the interference to other users is reduced, and the advantages of using SSDT under soft handover are fully utilized.

Description

A power control method for base station selection diversity transmission

technical field

The invention belongs to the technical field of mobile communication applications, and in particular relates to a power control method under selective diversity transmission of a base station in a WCDMA (wideband code division multiple access) mobile communication system using SSDT technology.

Background technique

SSDT (Site Selective Diversity Transmit) technology is one of the important technologies in advanced mobile communication systems. It is a macro-diversity method under soft handover and is adopted in WCDMA systems. By controlling certain cells not to transmit service data, the interference of multi-cell transmission to other users is reduced.

In this method, UE (User Equipment) selects a cell from the active set to be set as the primary cell, while other cells in the active set are non-primary cells. The main purpose is to only transmit service data from the primary cell, and non-primary cells do not transmit service data, so as to reduce the interference to other users caused by multi-cell transmission in soft handover mode, and also ensure that the UE can obtain data without network participation. Fast base station selection ensures the advantage of soft handover.

Under SSDT, the main cell sends DPDCH (Dedicated Physical Data Channel) and DPCCH (Dedicated Physical Control Channel) at the same time, while the non-primary cell does not send DPDCH, but only sends DPCCH. The purpose of sending DPCCH is to maintain the connection between the cell and the UE on the one hand. , on the other hand for power control. In this way, by not sending the DPDCH in the non-primary cell, interference to other users in the cell can be avoided.

FIG. 1 is a diagram of a time slot structure for downlink transmission of DPCH, where DPDCH and DPCCH are time-division multiplexed. In the system, a cell manages two downlink transmission power levels: P1 and P2. P1 is used to set the transmission power of the downlink DPCCH. The actual transmission power of TFCI (transport format combination indication), TPC (transmission power control) and PILOT (pilot) in DPCCH is P1 plus the defined bias power PO1, PO2 and PO3. P2 is used for downlink DPDCH. If the cell is selected as the primary cell, then P2 is equal to P1, otherwise, P2 is equal to 0, and the cell controls P1 and P2 within the dynamic range of power control. Fig. 2A and Fig. 2B are schematic diagrams of transmitting power of primary cell and non-primary cell under SSDT respectively.

Figure 3A and B are respectively a standard about 3GPP (Third Generation Partnership Project) published on WWW.3GPP.0RG website in December 2001: 3GPP TS.214 "physical layer procedures (FDD)" proposed by NEC Schematic diagram of the transmit power of the primary cell and non-primary cell under the S-SSDT and M-SSDT schemes. In the improved methods of S-SSDT and M-SSDT proposed by NEC, the primary cell transmits DPCCH and DPDCH, and non-primary cells do not.

For a certain UE in SSDT mode, when UTRAN sends downlink service data information to it through DPCH, the primary cell transmits DPDCH and DPCCH, while the non-primary cell only transmits DPCCH. DPCCH includes PILOT, TPC and TFCI, among which PILOT and TPC are for power control between UE and cell, pilot frequency provides frame boundary positioning at the same time, and TFCI is used to indicate the transmission format of service data. When the UE does not use the PDSCH (Physical Downlink Shared Channel) channel of the cell, it can obtain the transmission format of the DPDCH service data information through the DPCCH TFCI information sent by the primary cell. At this time, the TFCI field sent by the non-primary cell has no effective effect. The TFCI with the transmission power of P1+PO1 will cause interference to other users in the cell; when the UE uses the PDSCH channel of a certain cell, the data information transmission format on the PDSCH channel is carried in the TFCI domain of the relevant DPCCH. Whether the cell is a non-primary cell, the cell must deliver TFCI information so that the UE can decode the PDSCH channel of the cell through the TFCI domain. Moreover, the TPC field issued by the non-primary cell has little effect on uplink power control, and the TPC with the transmission power of P1+PO2 will cause interference to other users in the cell.

Contents of the invention

The present invention aims at the defect caused by the DPCCH control information transmitted by the non-primary cell, and proposes an improved power control method under the selection diversity transmission of the base station. The method is based on whether the UE uses the PDSCH channel of a cell in the active set. The transmission power of the DPCCH of the non-primary cell, so as to reduce the interference to other users in the cell.

In order to realize the purpose of the present invention, the technical measures taken by the present invention are: a power control method under the base station selection diversity transmission, the base station selects the power under the diversity transmission as the downlink dedicated physical channel transmission power, and the downlink transmission power includes P1 and There are two levels of P2, among which: P1 is used to set the transmission power of the downlink dedicated physical control channel, and P2 is used to set the transmission power of the downlink dedicated physical data channel. When the cell is selected as the primary cell, P2 is equal to P1, otherwise P2 is equal to 0 The transmission power of the dedicated physical control channel includes transmission format combination indication, transmission power control and pilot frequency, wherein: the transmission power of transmission format combination indication is P1+offset power PO1, and the transmission power of transmission power control is P1+offset Power PO2, the transmit power of the pilot is P1+bias power PO3; the transmit power of the main cell is: P1+(P1+PO2)+(P1+PO1)+(P1+PO3),

Its characteristic is that the transmission power of the non-primary cell is processed separately for the two cases of whether the UE (user equipment) uses the downlink physical shared channel of the activated centralized cell; where:

When the user equipment uses the downlink physical shared channel (PDSCH channel) of a certain cell in the active set, the transmission power control power of the non-primary cell dedicated physical control channel (DPCCH channel) is set to 0, and the transmission format combination indicator and pilot frequency The power is respectively set to P1+PO1 and P1+PO3;

When the user equipment does not use the downlink physical shared channel (PDSCH channel) of a cell in the active set, the transmission power control, transmission format combination indication and pilot power of the non-primary cell dedicated physical control channel (DPCCH channel) are all set to 0.

Since the present invention adopts the above technical solution, UTRAN transmits downlink service data through DPCH, when using SSDT method, if the UE does not use the PDSCH channel of a non-primary cell in the active set, the non-primary cell can turn off its DPDCH output and DPCCH Output (that is, no signal transmission); if the UE uses the PDSCH channel of a non-primary cell in the active set, the non-primary cell can turn off its DPDCH output and TPC output of the DPCCH (that is, no signal transmission). Through the present invention, the interference to other users can be reduced, and the advantages of adopting SSDT under soft handover can be brought into full play.

Description of drawings

The specific performance characteristics of the present invention are further illustrated by the following examples and accompanying drawings.

FIG. 1 is a diagram of a time slot structure for downlink transmission of DPCH (where DPDCH and DPCCH are time-division multiplexed).

FIG. 2A and FIG. 2B are schematic diagrams of the DPCH transmission power of the primary cell and the DPCH transmission power of the non-primary cell under the existing SSDT method, respectively.

FIG. 3A and FIG. 3B are schematic diagrams of the DPCH transmission power of the primary cell and the DPCH transmission power of the non-primary cell under the S-SSDT and M-SSDT schemes proposed by the existing NEC respectively.

FIG. 4A and FIG. 4B are respectively schematic diagrams of the DPCH transmission power of the primary cell and the DPCH transmission power of the non-primary cell (the UE uses the PDSCH channel of the non-primary cell) according to the present invention.

FIG. 5A and FIG. 5B are schematic diagrams of the DPCH transmission power of the primary cell and the non-primary cell in the present invention (the UE does not use the PDSCH channel of the non-primary cell).

Detailed ways

A power control method for base station selection diversity transmission, the downlink transmission power includes two levels of P1 and P2, wherein: P1 is used to set the transmission power of the downlink DPCCH dedicated physical control channel, and P2 is used to set the downlink DPDCH dedicated physical data channel When the cell is selected as the primary cell, P2 is equal to P1, otherwise P2 is equal to 0; the transmit power of the dedicated physical control channel includes TFCI, TPC and PILOT, wherein: TFCI is P1+PO1, and TPC is P1 +PO2, PILOT is P1+PO3; the transmit power of the primary cell is: P1+(P1+PO2)+(P1+PO1)+(P1+PO3), the transmit power of the non-primary cell depends on whether the UE user equipment uses the active set The PDSCH physical downlink shared channel of the primary cell is processed separately; where:

When the UE user equipment uses the PDSCH channel of a non-primary cell in the active set, the power of the TPC of the downlink DPCCH channel of the non-primary cell is set to 0, and the powers of TFCI and PILOT are respectively set to P1+PO1 and P1+PO3;

When the UE user equipment does not use the PDSCH channel of a non-primary cell in the active set, the powers of TPC, TFCI and PILOT of the downlink DPCCH channel of the non-primary cell are all set to 0.

Below in conjunction with Fig. 4, Fig. 5 more specifically illustrate the power control method under the SSDT of the present invention:

When under SSDT, when the UE does not use the PDSCH channel of a non-primary cell in the active set, the non-primary cell can turn off its DPDCH output and DPCCH output (that is, no signal is transmitted); when the UE uses a non-primary cell in the active set When the PDSCH channel is used, the non-primary cell can turn off its DPDCH output and the TPC output of the DPCCH (that is, no signal is transmitted).

Usually a cell manages two downlink transmission power levels: P1 and P2. Where P1 is used to set the transmit power of the downlink DPCCH, the actual transmit power of TFCI, TPC and PILOT in the DPCCH is P1 plus a predefined PO1, PO2 and PO3 respectively, and P2 is used to set the transmit power of the downlink DPDCH.

As shown in Figure 4A and Figure 4B, if a certain cell is selected as the primary cell, then the P2 of the cell is equal to P1, and the powers of TFCI, TPC, and PILOT are set to P1+PO1, P1+PO2, and P1+PO3 respectively; otherwise If a certain cell is selected as a non-primary cell, P2 is equal to 0. When the UE uses the PDSCH channel of a non-primary cell in the active set, the TPC power of the downlink DPCCH channel of the non-primary cell is set to 0, and the TFCI and PILOT The power is set to P1+PO1 and P1+PO3.

As shown in Figure 5A and Figure 5B, when the UE does not use the PDSCH channel of a non-primary cell in the active set, the power of TPC, TFCI and PILOT are all set to 0,

When the UE does not use the PDSCH channel of a non-primary cell in the active set, for the DPCCH on the non-primary cell, the TFCI, TPC, and PILOT information carried by it will not play an effective role, and its transmit power will also bring other users Therefore, in this case, turning off the DPCCH transmission of the non-primary cell can bring performance gain; when the UE uses the PDSCH channel of a non-primary cell in the active set, for the DPCCH on the non-primary cell, The TFCI information it carries is used to decode the data on the PDSCH channel, and the PILOT information is used for frame boundary positioning. The TPC field does not play an effective role, and its transmission power will also cause interference to other users. Therefore, in this case In this case, turning off the TPC domain transmission of the DPCCH of the non-primary cell can bring performance gain.

Claims (1)

1. A power control method under the base station selection diversity transmission, the base station selects the power under the diversity transmission as the transmission power of the downlink dedicated physical channel, and the downlink transmission power includes two levels of P1 and P2, wherein: P1 is used to set the downlink dedicated physical channel transmission power. The transmission power of the physical control channel, P2 is used to set the transmission power of the downlink dedicated physical data channel, when the cell is selected as the primary cell, P2 is equal to P1, otherwise P2 is equal to 0; the transmission power of the dedicated physical control channel includes transmission Format combination indication, transmission power control and pilot, where: the transmission power of transmission format combination indication is P1+offset power PO1, the transmission power of transmission power control is P1+offset power PO2, and the transmission power of pilot is P1+offset power PO3; the transmit power of the primary cell is: P1+(P1+PO2)+(P1+PO1)+(P1+PO3), It is characterized in that the transmission power of the non-primary cell is processed separately for two cases of whether the user equipment uses the downlink physical shared channel of the activated concentrated cell; wherein: When the user equipment uses the downlink physical shared channel of a certain cell in the active set, the power of the transmission power control of the dedicated physical control channel of the non-primary cell is set to 0, and the power of the transmission format combination indicator and pilot is set to P1+PO1 and P1+PO3; When the user equipment does not use the downlink physical shared channel of a certain cell in the active set, the transmission power control, transmission format combination indication and pilot power of the non-primary cell dedicated physical control channel are all set to 0.

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