Control of transfer capacity in radio station

FIELD OF THE INVENTION

The invention relates to a radio, the radio comprising a transceiver, a method of operating a radio station and a method of operating a radio system comprising a radio.

BACKGROUND OF THE INVENTION

In systems such as high speed packet access in the uplink (HSUPA) for UMTS (Universal Mobile Telecommunications System), mobile station (MS) transmitting a control signal together with digital signal data, wherein during periods when the data signal is not transmitted, the transmission control signal continues.

Transmit power level control signal can be reduced during periods when the interrupted data transfer than is saved power and reduces the average interference causes the gears, and increased for at least some transmission periods of the data signal, which enables reliable reception of the control signal .

Systems like UMTS, power control is used in a closed circuit, wherein the transmit power is regulated via MS transmission power control command (TPC) received from one or more base stations (BS). The power control commands are typically generated by the BS by comparing with a predetermined level ratio "signal-to-interference" (SIR) of the control signal received from the UE, and generate command "decrease" if the SIR is higher than a predetermined level, or a command to "increase" if SIR is below a predetermined level. Consequently, if one wants to increase the level of the transmission power control signal when transmission of the data signal, it is also necessary to increase the predetermined level of SIR, to avoid that any step in the power applied to MS, has been compensated for in a short period of time in response to control commands power stations BS c generated using the previous set level SIR.

Ideally, the predetermined SIR adjustment would apply to the BS in synchronism with each change in the above transmission power control signal. This can be achieved, if the BS detects rapidly when it was applied change transmission power control signal, for example, by detecting the beginning of data transmission.

However, in practice, to the BS it may be difficult to detect when a change has been applied transmission power control signal before the control closed loop power offset the change in the transmission power control signal. For example, in UMTS power control commands are transmitted in each time slot (0.666 ms). If, for example, to the transmission power control signal is applied the change is 3 dB and the power control for the internal circuit is used in step of 1 dB, while the power control internal loop completely balances change transmission power control signal for the three time slots. If the BS is to avoid any balancing power control internal loop, it has less than one time slot for which the application is required to detect increasing transmit power control signal.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved power control.

According to a first aspect of the invention there is provided a method of operating a radio station, comprising the steps of:

simultaneously transmit a continuous control signal and a digital data signal;

take first and second transmission power control command;

adjust transmission power by that

• in response to the first power control commands to increase transmission power by the power step,

• in response to the second power control commands to decrease transmission power by the power step,

wherein the method further comprises the step of temporarily changing the response to power control commands in response to the initiation or termination of data signal transmission.

According to a second aspect of the invention there is provided a radio station comprising:

a transmitter adapted to simultaneously transmit a continuous pilot signal and a digital data signal;

a receiver configured to receive first and second power control commands, and

Power control means arranged to control the transmission power of the transmitter by

• increasing the transmission power step power in response to the first power control commands,

• reducing the transmission power by the power step in response to the second power control command,

wherein the power control means is arranged to temporarily change the response to power control commands in response to the initiation or termination of data signal transmission.

In one embodiment, the modified response to the power control command may involve refraining from transmission power control in response to at least some of the power control command.

In another embodiment, the modified response to power control commands includes power control transmit power of another step size.

Next, an example will be described the invention with reference to the accompanying drawing.

Drawing - a block diagram of a radio communication system comprising a station sends data and receive data station.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will be described with reference to UMTS, and sending the data station is a mobile station (MS), and the receiving data station is a base station (BS). According to the present invention, the MS changes the algorithm used to respond to power control commands for a period of time after the change of transmission power control signal relating to the beginning or end of the data signal.

The period during which changes a power control algorithm may be pre-defined or the BS may inform the MS of it. Notification can also be used to activate / deactivate change the MS power control algorithm.

Various embodiments of the invention may include various changes in the power control algorithm.

In one embodiment, the change station MS involves ignoring certain power control commands in a closed circuit during said time period. This provides for the BS to detect time window that begin transmitting data signal and a predetermined SIR adjustment without having to shift the power control signal was balanced power control in a closed loop.

Power control commands are ignored for a period of time, can be any of the following commands:

- All received power control commands,

- The team's only "enhance"

- The team's only "reduce"

Badge power control commands are to be ignored, can depend on the direction of the previous change in the transmission power control signal. In one example of this embodiment typically MS adjusts the transmit power of its control signal once per time slot in response to power control commands received from the BS. MS uses an additional increase in the transmission power of its control signal when it starts transmitting data signal and applies an additional decrease its transmission power control signal when it completes the transfer of the data signal. According to this embodiment of the invention, MS ignores the power control command "lower", adopted in the first n1 timeslots after applying an additional increase in the transmit power of its control signal. MS maintains its transmit power constant control signal during this period.

In some variations of this embodiment, the MS can ignore power control command "increase", adopted in the first n2 timeslots after applying further reduce the transmission power of its control signal.

In a further variation of this embodiment, the MS can also ignore the command to "increase" the power control just prior to receiving the command, which has a sign opposite to ignore commands. Receiving team has the opposite sign ignored commands, MS can be interpreted as an indication that the BS has successfully handled its predetermined SIR. For example, after the application of increasing the transmission power control signal in response to the start signal the MS may ignore the command "lower" before the first command to "increase." Note that in this case, notification of the length of the time period is hidden in themselves the power control commands. As a further variation of the MS may ignore the command "downgrade" to the earlier of the receipt of a command "raise" prior to the expiration time slots n1. Similarly, after applying the power reduction control signal in response to the termination signal the MS may ignore the command "increase" to the reception of the first command "lower" or to an earlier command reception from "lower" and expiration time slots n2.

In a variation of any of the above-described embodiment, the BS can send a clear signal to the MS to indicate that the MS must complete the change of the power control algorithm (assuming that the predetermined adjusted SIR).

In the second embodiment, the power control algorithm change involves switching between two predetermined power control algorithm, for example, with an algorithm which is responsive to a power control command from the first frequency on an algorithm which is responsive to power control commands at a second frequency. For example, in UMTS provided with two power control algorithm: first algorithm, wherein the MS responds to the power control command received at each time slot and a second algorithm by means of which the MS changes its transmit power only if a certain number (5 in UMTS) consecutive power control commands received in one direction. MS, which usually responds to power control commands using a first algorithm switches to a response using the second algorithm into first n1 timeslots after applying further increase its transmission power control signal, to return to use the first algorithm.

There may be used the same methods completed using a second algorithm, as in the first embodiment.

In another embodiment, the power control algorithm change involves changing the step size of power (e.g., 1 dB 0.5 dB).

In variations of these embodiments property changes the power control algorithm may depend on the change amount of transmit power applied to the control signal. For example, the frequency response to the power control commands can be reduced to a larger value when the change amount of transmission power control signal less.

In any of these embodiments the values ​​of n1 and n2 may be the same, and warning may occur simultaneously or separately. In some variations n1 and / or n2 may be equal to the length of the transmission data signal. In the case of the first embodiment, this means that the transmission power control signal (and possibly also the data signal) would remain constant during the transmission of the data signal. The value n1 is usually a compromise between efficiency losses stemming from the modified functioning of the power control closed loop, and increase efficiency, the invention derives from the ability to prevent the decrease in pitch power applied to the control channel, the action of the power control closed loop.

In the drawing it is illustrated a block diagram of a radio communication system, comprising the MS 100 and the BS 200.

MS 100 includes a processor (μP), connected to an input 110 for receiving data to be transmitted in a data signal.

Processor 120 is configured to divide data into a plurality of data packets, data packets are encoded for transmission and to control the time during which there is a transfer of data packets. Processor 120 is connected with the transmitter (Tx) 150 for transmitting signal data via an antenna 160. The transmission signal is discrete data, so as, for example, receipt of the input data 110 is discrete, or because the MS 100 is given permission to transmit data only during discrete time periods, or because there is a need to prepare for the MS handover. The data signal for transmission is supplied to transmitter 150 from processor 120 through the power control section 130 of the data signal.

Processor 120 is also configured to generate a control signal such as a pilot signal comprising predetermined symbols suitable for channel estimation by the base station BS, and is connected to the transmitter 150 through the power control section 140 a control signal that sets the transmit power level control signal. The control signal is continuously transmitted, while the transmitted data signal, and while the signal transmission is interrupted. Section 140 controls the power control signal is connected to the controller 170 output for controlling the transmission power level control signal for transmission of data, for which levels may be dependent on the transmission format of the data signal, and for controlling the transmit power level control signal, while a data signal interrupted. Power controller 170 is connected to the processor 120 which notifies it when data is being transferred.

MS 100 includes a coupled to an antenna 160 receiver (Rx) 180 for receiving TPC commands transmitted by the base station BS 200 for controlling transmission power in a closed circuit, and a controller 170 output is coupled to the receiver 180 for decoding the received TPC commands and coupled to the transmitter 150 for adjusting the transmit power level control signal and the data signal in accordance with the received TPC commands. Transmission power control closed loop is superimposed on the changes in transmit power level introduced by the power control section 140 of the control signal.

Power controller 170 may be coupled to the transmitter 150 for control step size for the power to be used in controlling the transmission power in response to the TPC command, as described herein.

Power controller 170 is configured to control transmission power as described herein.

BS 200 includes antenna 270 coupled to receiver (Rx) 210 for receiving a control signal and data signal transmitted by the mobile station MS 100. The demodulator (D) 220 is coupled to the receiver 210 for demodulating the received data signal and sending the demodulated data output 230.

Means (E) 240 is connected to the receiver estimates 210 for performing channel estimation, such as received pilot symbols to a control signal. Yield estimation means 240 may be coupled to the data demodulator 220 to enable use of the result of channel estimation in the demodulation data, for example, to make it possible to generate a demodulator reference phase data 220 or performing stabilization.

BS 200 comprises a processor (μR) 250, which is connected to the output estimation means 240 for generating TPC commands and coupled to a transmitter (Tx) 260 for transmitting the TPC commands to the first station 100 via the antenna 270. In order to generate TPC commands evaluation tool 240 Measured parameters received control signal, such as SIR or SNR, and compares the measured parameter with a predetermined value. When the MS 100 increases the transmission power level of the control signal during data transmission, the TPC commands tend to restore the transmission power level of the MS 100, without further action on the BS 200. Thus, the CPU 250 increases the predetermined value of the measured parameter by a corresponding amount, which may vary the format of the data signal, the period during which the transmit power level of the control signal is temporarily increased.

Although the invention has been described with reference to UMTS, the invention may be used in other wireless communication systems such as cdma2000.

In the present specification and claims, reference to an element in the singular does not exclude the presence of a plurality of such elements. Furthermore, the word "comprising" does not exclude the presence of other elements or steps than those listed. Inclusion reference numerals in parentheses in the claims is directed to further understanding and is not intended to limit.

Other changes will become apparent to those skilled in the art upon reading this disclosure. Such changes may involve other features which are already known in radio communication systems and which may be used instead of features already described herein or in addition to them.