Apparatus and method for controlling transmission power in an NB-TDD CDMA communication system
First Claim
1. A transmission power control method in a UE (User Equipment) for a TDD (Time Division Duplexing) CDMA (Code Division Multiple Access) communication system which transmits a stream of frames from a Node B to the UE, each of the frames including a field indicating power level information transmitted from the Node B and a time slot field for allocating a TPC (Transmission Power Control) command and transmission data from the Node B to the UE, wherein the UE receives data transmitted from the Node B, allocated to a time slot field in a following frame after a transmission pause period where no transmission data exists in the time slot fields in specific frames among the stream of frames transmitted from the Node B to the UE, comprising the steps of:
- measuring a propagation loss between the Node B and the UE by receiving the power level information at a specific time slot in the transmission pause period;
measuring an interference noise of the Node B by receiving a specific channel signal broadcast by the Node B;
determining uplink transmission power by summing up (i) values determined by applying a weight based on a length of the transmission pause period to the currently measured propagation loss and an average propagation loss between the Node B and the UE during the transmission pause period, (ii) a predetermined target signal-to-interference ratio (SIR), (iii) the measured interference noise of the Node B, and (iv) an offset for compensating for the propagation loss error; and
transmitting a TPC command corresponding to the determined uplink transmission power to the Node B.
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Accused Products
Abstract
A TDD (Time Division Duplexing) CDMA (Code Division Multiple Access) communication system performs power control in a closed-loop power control mode in a data transmission period, but performs the power control using a modified open loop power control method and an open loop power control method as well as the closed-loop power control method in a transmission pause period, thereby to properly set initial transmission power after the end of the transmission pause period.
128 Citations
13 Claims
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1. A transmission power control method in a UE (User Equipment) for a TDD (Time Division Duplexing) CDMA (Code Division Multiple Access) communication system which transmits a stream of frames from a Node B to the UE, each of the frames including a field indicating power level information transmitted from the Node B and a time slot field for allocating a TPC (Transmission Power Control) command and transmission data from the Node B to the UE, wherein the UE receives data transmitted from the Node B, allocated to a time slot field in a following frame after a transmission pause period where no transmission data exists in the time slot fields in specific frames among the stream of frames transmitted from the Node B to the UE, comprising the steps of:
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measuring a propagation loss between the Node B and the UE by receiving the power level information at a specific time slot in the transmission pause period;
measuring an interference noise of the Node B by receiving a specific channel signal broadcast by the Node B;
determining uplink transmission power by summing up (i) values determined by applying a weight based on a length of the transmission pause period to the currently measured propagation loss and an average propagation loss between the Node B and the UE during the transmission pause period, (ii) a predetermined target signal-to-interference ratio (SIR), (iii) the measured interference noise of the Node B, and (iv) an offset for compensating for the propagation loss error; and
transmitting a TPC command corresponding to the determined uplink transmission power to the Node B. - View Dependent Claims (2, 3)
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4. A transmission power control method in a UE for a TDD CDMA communication system which transmits a stream of frames from a Node B to the UE, each of the frames including a field indicating power level information transmitted from the Node B and a time slot field for allocating a TPC command and transmission data from the Node B to the UE, wherein the UE receives data transmitted from the Node B, allocated to a time slot field in a following frame after a transmission pause period where no transmission data exists in the time slot fields in specific frames among the stream of frames transmitted from the Node B to the UE, comprising the steps of:
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measuring a first propagation loss between the Node B and the UE by receiving the power level information at a specific time slot in the transmission pause period;
detecting an offset determined considering (i) uplink transmission power used at a time slot just before the transmission pause period, (ii) a second propagation loss between the Node B and the UE at the time slot just before the transmission pause period, (iii) a TPC command received from the Node B at the time slot just before the downlink transmission pause period, and (iv) a change in channel environment between the Node B and the UE; and
determining first uplink transmission power by summing up (a) the uplink transmission power used at the time slot just before the transmission pause period, (b) a value determined by subtracting the second propagation loss from the first propagation loss, and (c) the offset. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A transmission power control apparatus in a UE for a TDD CDMA communication system which transmits a stream of frames from a Node B to the UE, each of the frames including a field indicating power level information transmitted from the Node B and a time slot field for allocating a TPC command and transmission data from the Node B to the UE, wherein the UE receives data transmitted from the Node B, allocated to a time slot field in a following frame after a transmission pause period where no transmission data exists in the time slot fields in specific frames among the stream of frames transmitted from the Node B to the UE, comprising:
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an uplink transmission power controller for, upon occurrence of the transmission pause from a specific channel signal received from the Node B, measuring a propagation loss between the Node B and the UE based on power level information received at a specific time slot in the transmission pause period, detecting an interference noise of the Node B from the specific channel signal, and determining uplink transmission power by summing up (i) values determined applying a weight based on a length of the transmission pause period to the currently measured propagation loss and an average propagation loss between the Node B and the UE during the transmission pause period, (ii) a predetermined target SIR, and (iii) an offset for compensating for the propagation loss error;
a downlink TPC command generator for generating a downlink TPC command for controlling downlink transmission power to be transmitted by the Node B at the following frame by receiving uplink transmission power determined by the uplink transmission power controller;
a multiplexer for multiplexing the downlink TPC command, user data to be transmitted to the Node B, and TFCI (Transport Format Combination Indicator) indicating a type and a data rate of the user data; and
a multiplier for multiplying the uplink channel signal by a channel gain based on the determined uplink transmission power. - View Dependent Claims (12)
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13. A transmission power control apparatus of a Node B in a UE for a TDD CDMA communication system which transmits a stream of frames from a Node B to the UE, each of the frames including a field indicating power level information transmitted from the Node B and a time slot field for allocating a TPC command and transmission data from the Node B to the UE, wherein the Node B transmits data to the UE in a following frame after a transmission pause period where no transmission data exists in the time slot fields in specific frames among the stream of frames transmitted from the Node B to the UE, comprising:
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a demultiplexer for demultiplexing an uplink channel signal received from the UE into a downlink TPC command, user data from the UE, and TFCI indicating a type and a data rate of the user data;
a downlink transmission power controller for determining downlink transmission power for the UE based on the downlink TPC command, upon detecting an occurrence of transmission pause;
an uplink TPC generator for generating an uplink TPC command for controlling uplink transmission power to be transmitted to the UE at the following frame by receiving uplink transmission power determined by the downlink transmission power controller;
a multiplexer for multiplexing the generated uplink TPC command, the user data to be transmitted to the UE, and TFCI indicating a type and a data rate of the user data; and
a multiplier for multiplying the downlink channel signal by a channel gain based on the determined downlink transmission power.
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Specification