MXPA01009199A - Outer loop/weighted open loop power control in a time division duplex communication system - Google Patents

Abstract

Outer loop/weighted open loop power control controls transmission power levels in a spread spectrum time division duplex communication station. A first communication station (110) transmits a communication to a second communication station including target adjustment information generated at the first station on the basis of measured error rates of communications from the second station to the first station. The second station receives the communication and measures its received power level. Based on in part the received communication's power level and the communication's transmission power level, a path loss estimate is determined. A quality of the path loss estimate is also determined. The transmission power level for a communication from the second station to the first station is based on in part weighting the path loss estimate in response to the estimate's quality and based on the receive target adjusted by the target adjustment information transmitted from the first station.

Description

EXTERNAL CIRCUIT ENERGY CONTROL / WEIGHTED OPEN CIRCUIT IN A COMMUNICATION SYSTEM BILATERAL SIMULTANEOUS DIVISION OF TIME BACKGROUND OF THE INVENTION This invention relates in general to simultaneous time division, spread spectrum (TDD) bilateral communication systems More particularly, the present invention relates to a system and a method for controlling the transmission energy within the system. TDD communication system Figure 1 describes a simultaneous bilateral spread-spectrum, wireless (TDD) time communication system The system has a plurality of base stations 30? -307 Each base station 30? communicates with a user equipment (UEs) 32? -32 in its area of operation Communications transmitted from base station 30? to UE 32? are referred to as downlink communications and communications transmitted within a UE 32a. base 30 ?, are referred to as uplink communications.In addition to communication over different frequency spectra, TDD extended spectrum systems an multiple communications on the same spectrum. The multiple signals are distinguished with their respective microcircuit code sequences (codes). Also, to more efficiently use the spread spectrum, the TDD systems as illustrated in Figure 2, use respective frames 34 divided by a number of time slots 36? -36n, such as sixteen time slots. In such systems, a communication is sent at selected time intervals 31? -36n using selected codes. Consequently, a frame 34 is capable of carrying multiple communications distinguished by time interval and by code. The combination of a simple code in a resource. Based on the bandwidth required to support a communication, one or more resource units are assigned to that communication. Most TDD systems adaptively control the transmission energy levels. In a TDD system, many communications can share the same time interval and spectrum. When an EU 32? or a base station 30? is receiving a specific communication, all other communications that use the same time interval and spectrum cause interference to the specific communication. Increasing the transmission power level of a communication degrades the signal quality of all other communications within this time interval and spectrum. However, reducing the transmission power level much further results in undesirable signal-to-noise ratios (SNRs) and also undesirable bit error rates (BERs) in the receivers. To maintain the signal quality of the communications and the low levels of transmission energy, the transmission power control is used. A method that uses transmission power control in a code division multiple access (CDMA) communication system is described in U.S. Patent No. 5,056,109 (Gilhousen et al). A transmitter sends a communication to a particular receiver. After reception, the energy of the received signal is measured. The energy of the received signal is compared to a received, desired signal energy. Based on the comparison, a control bit is sent to the transmitter either by increasing or decreasing the transmission energy by a fixed amount. Since the receiver sends a control signal to the transmitter to control the energy level of the transmission, such energy control techniques are commonly referred to as a closed circuit. Under certain conditions, the operation of closed loop systems is degraded. For example, if communications sent between a UE and a base station are in a highly dynamic environment, such as due to the movement of the UE, such systems may not be able to adapt sufficiently to compensate for the changes. The rate or refresh rate of the closed-circuit power control in the TDD is typically 100 cycles per second, which is not enough for fast attenuation channels. WO 98 45962 A describes a method for controlling a transmission energy level of a mobile terminal in a satellite communication system. The energy control method has a closed loop element and an open circuit element. For the closed circuit element, the base station calculates the energy setting of the mobile terminal based on the strength of the signals received from the mobile terminal. The base station takes into account the propagation delays of the satellite system in determining the power setting.

For the open circuit element, the strength of the received signal from the base station in each frame is compared to the strength of the signal received in the previous frame. The energy or transmission power of the mobile terminal is adjusted inversely with the variations in the strength of the observed signal. U.S. Patent No. 5,542,111 describes a method for regulating the control of transmission energy in a mobile station, using control of long-term and short-term transmission energy. Long-term power control occurs at a base station above the upper level forming a closed control circuit. A statement from the decision authority is communicated from the base station to the mobile station. The energy level of short-term transmission is determined on the lower circuit using a long-term energy identifier and decision authority. Accordingly, there is a need for alternative procedures to maintain signal quality and low levels of transmission energy.

BRIEF DESCRIPTION OF THE INVENTION The external circuit / weighted open circuit energy control controls the transmission energy levels in a simultaneous, split-time, spread spectrum bilateral communication system. In a first communication station, errors are measured in a communication received from a second communication station. Based, in part, on the measured errors, an adjustment is determined at an objective level. The first station transmits a communication and the objective adjustment to the second station. The second station measures the energy level received from the communication of the first station. Based, in part, on the energy level received, a loss of propagation is determined. The target level is adjusted in response to receiving the target adjustment. The quality of the propagation loss is determined with respect to a subsequent communication that is to be transmitted from the second station. The transmission energy level of the second station for subsequent communication is adjusted based, in part, on the determined propagation loss, the determined quality and the adjusted target level.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a TDD system of the prior art. Figure 2 illustrates time intervals in repeated frames of a TDD system. Figure 3 is a flow diagram of the energy control of the weighted open circuit / outside circuit. Figure 4 is a component diagram of two communication stations using the outdoor circuit / weighted open circuit power control. • Figure 5 is a graph of the operation of the outdoor circuit / open circuit, weighted open circuit and closed circuit power control systems. Figure 6 is a graph of the operation of three systems, in terms of the Block Error Ratio (BLER).

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Preferred embodiments will be described with reference to the figures of the drawings, with similar numbers representing similar elements throughout. The outdoor circuit / weighted open circuit energy control will be explained using the flow chart of Figure 3 and the components of two simplified communication stations 110, 112 as shown in Figure 4. For the following arrangement, the communication having its controlled transmitter power, is referred to as the transmitting station 112 and the communication station receiving the energy controlled communications, is referred to as the receiving station 110. Since the outside circuit / weighted open circuit power control can be used for uplink, downlink or both types of communications, the transmitter that has its energy controlled can be associated with the base station 30 ?, UE 32? or both. Accordingly, if they are used in the uplink and downlink power control, the components of the receiving and transmitting station are associated with the base station 30? and the EU 32 ?. The receiving station 110 receives various radio frequency signals including communications from the transmitting station 112 using an antenna 78, or alternatively, an antenna array, step 38. The received signals are passed through an isolator 66 to a demodulator 68 to produce a baseband signal. The baseband signal is processed, such as by the channel estimation device 70 and a data estimation device 72, at the time intervals and with the appropriate codes assigned to the communication of the transmitting station. The channel estimation device 70 commonly uses the training frequency component of the baseband signal, to provide the channel information, such as the channel impulse responses- The channel information is used by the device 72 of the channel. data estimation, the interference measurement device 74, and the device 76 for calculating the transmission energy. The data estimation device 72 retrieves the data from the channel by estimating the transient symbols using the channel information. Prior to transmission of the communication from the transmitting station 112 the communication data signal is encoded in error using an error detection / correction encoder 110. The error coding scheme is typically a circular redundancy code (CRC), followed by a forward error correction coding, although other types of error coding schemes may be used. Using the transient symbols produced by the data estimation device 72, an error detection device 112 detects errors in the transient symbols. A processor 111 analyzes the detected error and determines a proportion of errors for the received communication, step 39. Based on the error rate, the processor 111 determines the amount, if any, of an objective level, such as a signal ratio target to interference (SIRob: et? vo) / needs to be changed in the transmit station 112, step 40. Based on the determined amount, a target setting signal generated by the target setting generator 114. The target setting is subsequently sent to the transmitting station, step 41. The objective setting signalized to the transmitting station 112, such as by the use of a dedicated or reference channel. A technique for determining the amount of adjustment at the target level uses a higher and a lower threshold. If the error ratio determined II exceeds a higher threshold, the target level is adjusted to an unacceptably low level, and needs to be increased. A target level adjustment signal is sent indicating an increase in the target level. If the determined error rate is below a second threshold, the target level is adjusted to an unnecessarily high level and the target level can be decreased. By reducing the target level, the energy level of the transmission station is decreased, reducing the interference to other communications using the same time interval and the same spectrum. To improve the operation, as soon as the error ratio exceeds the upper limit, an objective adjustment is sent. As a result, the high error rates are improved rapidly and the low error rates are adjusted slowly, such as once in 10 seconds. If the error ratio is between the thresholds, an objective adjustment is not sent maintaining the same target level. Next, the application of the prior art to a system using the CRC and FEC quantification is shown. Each CRC block is verified for an error. Each time a frame is determined as having an error, a counter is incremented.

As soon as the counter exceeds a higher threshold, such as 1.5 to 2 times the desired block error rate (BLER), an objective setting is sent by increasing the target level. To adjust the SIR0b3et? or in the transmitting station 112, is the increment in the SIR0b3et sent? or (SIRINC) / which is typically in a range of 0.25 dB to 4 dB. If the found number of CRC frames exceeds a predetermined limit, such as 1,000 blocks, the value of the counter is compared to a lower threshold, such as 0.2 to 0.6 times the desired BLER. If the number of block errors counted is below the lower threshold, an objective adjustment signal is sent by lowering the target level, SIRDEC. A typical SIRDEC interval is 0.25 to 4 dB. The SIRDEC value can be based on SIR? NC and a target block error ratio, BLERob: iet? Vo. The BLERob3et is based on the type of service. Equation 1 illustrates a procedure of this type for the determination of SIRDEC.

S I RDEC- S I RoNc BLERob? etivo / (l - BLER0be3 tt ive / Equation 1 If the count is between the thresholds for the predetermined block limit, a target adjustment signal is not sent in. Alternatively, a simple threshold can be used. exceeds the threshold, the target level is increased.If the error ratio is below the threshold, the target is decreased.Additionally, the target level adjustment signal may have several adjustment levels, such as from 0 dB to ± 4 dB in increments of 0.25 dB, based on the difference between the determined error ratio and the desired error rate The interference measurement device 74 of the receiving station 110 determines interference levels in dB, IRS, within the channel , based either on the channel information, or on the transient symbols generated by the data estimation device 72, or both, using the transient symbols and the channel information, the transmission energy calculating device 76 controls the transmit power level of the receiving station by controlling the gain of an amplifier 54. For use in estimating the propagation loss between the receiving and transmitting stations 110, 112 and the sending of data, the receiving station 110 sends a communication to the transmitting station 112, step 41. The communication can be sent on any of the various channels. Typically, in a TDD system the channels used for the estimation of propagation loss are referred to as reference channels, although other channels may be used. The receiving station 112 is a base station 30?, the communication is preferably sent on a common downlink channel or a common physical control channel (CCPCH). The data to be published on the transmitting station 112 on the reference channel are referred to as the data of the reference channel. The reference data may include, as shown, the IRS interference level, multiplexed with other reference data, such as the transmit power level, TRS. The interference level, IRS, and the energy level of the reference channel, IRS can be sent on other channels, such as a signaling channel. The data of the reference channel is generated by a reference channel data generator 56. The reference data, based on the communication bandwidth requirements. A dispersion and training sequence insertion device 58 disperses the data of the reference channel and makes the reference data broadcast or dispersed, multiplexed in time with a training sequence in the appropriate time intervals and the codes of the assigned resource units. The resulting sequence is called a sudden increase in communication. The sudden increase in communication is subsequently amplified by an amplifier 60. The sudden increase in amplified communication can be summed by a summing device 62 with any other sudden increase in communication created through the devices, such as a data generator 50, the device 52 of the insertion of the dispersing and training sequence, and the amplifier 54. The summed increments of communication are modulated by a modulator 64. The modulated signal is passed through an isolator 66 and is radiated by a antenna 78 as shown or, alternatively, through an antenna array. The radiated signal is passed through a radio channel 80, wireless, to an antenna 82 of the transmitting station 112. The type of modulation used for the transmitted communication can be any of those known to those skilled in the art, such such as direct phase shift manipulation (DPSK) or quadrature phase shift manipulation (QPSK). The antenna 82 or, alternatively, the antenna array in the transmitting station 112 receives various radio frequency signals, including the target settings. The received signals are passed through an isolator 84 to a demodulator 86 to produce a baseband signal. The baseband signal is processed, such as by a channel estimation device 88 and a data estimation device 90, at the time intervals and with the appropriate codes assigned to the sudden increase in communication of the receiving station 110. channel estimation device 88 commonly uses the component of the training sequence in the baseband signal to provide channel information, such as channel impulse responses. The channel information is used by the data estimation device 90 and an energy measurement device 92. The energy level of the processed communication corresponding to the reference channel, Rts, is measured by the energy measurement device 92 and sent to a propagation loss estimation device 94, step 42. The channel estimation device 88 the data estimation device 90 is capable of separating the reference channel from all other channels. If an automatic gain control device or controller is used to process the received signals, the measured energy level is adjusted to correct the gain of these devices either in the power measurement device 92 or in the measuring device 94. of the loss of propagation. The energy measuring device is a component of an outdoor circuit / weighted open circuit controller 100. As shown in Figure 4, the outdoor circuit / weighted open circuit controller 100 comprises the energy measurement device 92, the propagation loss estimating device 94, the quality measuring device 94, the target updating device 101, and the transmission energy calculation device 98. To determine the propagation loss, L, the transmitting station 112 also requires the transmitted communication power level, TRS. The level of energy transmitted in the communication, TRS, can be sent together with the data of the communication or in a signaling channel. If the energy level, TRS, is sent, together with the communication data, the data estimation device 90 interprets the energy level and sends the interpreted energy level to the device 94 for estimating the propagation loss. If the receiving station 110 is a base station 30 ?, preferably the level of transmitted energy, TRS, is sent via the broadcast channel (BCH) from the base station 30 ?. By subtracting the energy level of the received communication, RT ?, of the transmitted power level of the sent communication, TRS, the propagation loss estimation device 94 estimates the propagation loss, L, between the two stations 110, 112, step 43. In addition, a long-term estimate of the loss of propagation, Lo, is updated, step 44. An example of an estimate of the long-term loss of propagation is a long-term average. The long-term average of the propagation loss, L0, is an average of the estimates of the propagation loss. In certain situations, instead of transmitting the transmitted energy level, TRS, the receiving station 110 can transmit a reference for the transmitted energy level. In that case, the propagation loss estimation device 94 provides the reference levels for the propagation loss, L. Since the TDD systems transmit downlink and uplink communications in the same frequency spectrum, the conditions that these are Communications they experience are similar. This phenomenon is referred to as reciprocity. Due to the reciprocity, the propagation loss experienced by the downlink will also be experienced by the uplink and vice versa. By adding the estimated propagation loss to a target level, a transmission energy level is determined for a communication from the transmitting station 112 to the receiving station 110. If there is a time delay between the estimated propagation loss and the transmitted communication, the propagation loss experienced by the transmitted communication may differ from the calculated loss. In TDD, where communications are sent at different time intervals 36? -36n, the delay in the time interval between received and transmitted communications can degrade the operation of an open-circuit power control system. To overcome these drawbacks, the weighted open circuit energy control determines the quality of the estimated propagation loss, using a quality measurement device 96, step 45, and weights accordingly the estimated propagation loss, L, and the long-term average of the loss of spread, Lo. To improve the operation additionally in the outer circuit / weighted open circuit, an object level is set. A processor 103 converts the transient symbols produced by the data estimation device 90 to bits, and extracts the information from the objective setting, such as a SIR0bje i or t adjustment. A lens update device 101 adjusts the target level using the lens settings, step 46. The objective level may be a target level of energy received, target, at the receiving station 110. The energy calculation device 98 of Transmission combines the adjusted objective level with the estimated weighted propagation loss, L, and the long-term average of the estimated propagation loss, Lo, to determine the transmission energy level of the transmitting station, step 47.

The data to be transmitted in a communication from the transmitting station 112 are produced by the data generator 102. The data is encoded by error detection / correction, by the error detection / correction encoder 110. The encoded error data is disseminated and multiplexed in time with a training sequence by the insertion device 104 of the training sequence, at the appropriate time intervals and the assigned resource unit codes that produce a sudden increase in the communication. The broadcast signal is amplified by an amplifier 106 and modulated by the modulator 108 at radio frequency. The gain of the amplifier is controlled by the device 98 for calculating the transmission energy to achieve the determined transmission energy level. The sudden increase in communication, controlled in energy, is passed through the insulator 84 and is radiated by the antenna 82. The following is an algorithm for controlling the external circuit / weighted open circuit energy. The transmission energy level of the transmitting stations, in decibels, Pts, is determined using Equation 2.

PTS = S I ROBJECTIVE + I RS + CC (L-LO) + L0 + CONSTANT VALUE Equation 2 The SIROBJECTIVE has a value adjusted based on the objective adjustment signals received. For the downlink, the initial value of SIROBJECTIVE is known in the transmitting station 112. For the control of the uplink energy, SIROBJECTIVE is signaled from the receiving station 110 to the transmitting station 112. Additionally, a value can also be signaled maximum and minimum for a adjusted SIROBJECTIVE. The adjusted SIROBJECTIVE is limited to the maximum and minimum values. IRS is the measure of the interference energy level at the receiving station 110. L is the estimate of the propagation loss in decibels, TRS-RTS, for the most recent time interval 36? -36n, in which the loss of propagation It was estimated. L0, the long-term average of the propagation loss in decibels is the running average of the estimate of the propagation loss, L. The CONSTANT VALUE is a correction term. CONSTANT VALUE corrects differences in uplink and downlink channels, such as to compensate for differences in uplink and downlink gain. In addition, the CONSTANT VALUE can provide correction if the reference level of the transmission power of the receiving station is transmitted, instead of the effective transmission energy, TRS. If the receiving station 110 is a base station, the CONSTANT VALUE is preferably sent via a layer 3 message. The weighting value, a, is a measure of the quality of the estimated propagation loss and is preferably based on the number of time slots 36? -36n, between the time interval, n, of the last estimate of propagation loss and the first time interval of the communication transmitted by the transmitting station 112. The value of a is between zero and one . In general, if the difference in time between the time intervals is small, the estimate of the recent propagation loss will be clearly accurate and a is adjusted to a value close to one. In contrast, if the difference in time is large, the estimate of the loss of propagation may not be accurate and the measurement of the long-term average propagation loss is more likely to be a better estimate for the loss of propagation. Consequently, it is adjusted to a value close to one.

The equations are equations to determine. ce = 1 - (D-l) / (Dmax-l) Equation 3 a = max. { 1- (D-l) / (Dmax-perraitido-l) # 0.}. Equation 4 The value D is the number of time slots 36? -36n between the time interval of the last estimate of propagation loss and the first time slot of the transmitted communication that will be referred to as the time interval delay. If the delay is a time interval, a is one. Dmax is the maximum possible delay. A typical value for a table that has fifteen time intervals is seven.

If the delay is D "e s zero D max-pemit the delay of the maximum time interval, allowed, to use the open-circuit power control. If the delay exceeds Dmax-pem? T? Do? the open-circuit power control is effectively turned off by setting a = 0. Using the transmission power level, PTs determined by a transmission energy calculation device 98, the transmission power of the transmitted communication is adjusted. Figures 5 and 6 compare the operation of the weighted outdoor circuit / open circuit, open circuit and closed circuit systems. The simulations in Figures 5 and 6 were performed for a slightly different version of the weighted open circuit / outdoor circuit algorithm. In this version, the target SIR is updated in each block. A SIR0bjeti is incremented if a block error was detected, and decreased if the block error was not detected. The exterior circuit / weighted open circuit system used Equation 2. Equation 3 was used to calculate a. The simulations compared the operation of the systems that control the level of energy transmission of the UE's 32 ?. For the simulations, 16 CRC bits were compensated each block. In the simulation, each block was four frames. A block error was declared when at least two gross bit errors occur on a block. The uplink communication channel is assigned with a time interval per frame. The target for the rate or proportion of block errors is 10%. The SIR0BJECTIVE is updated for 4 frames. The simulations direct the operation of these systems for an UE 32? that travels at 30 kilometers per hour. The simulated base station used diversity of two antennas for reception, with each antenna having a three-finger RAKE receiver. The simulation approached a realistic channel and the SIR stimulation was based on a slow step sequence, field type 1 sudden increase, in the presence of additive white Gaussian noise (AWGN). The simulation used a Pedestrian Type B channel from the International Telecommunication Union (ITU) and the QPSK modulation. It was assumed that the interference levels had no uncertainty. The channel coding schemes were not considered. It is set to 0 db. The graph 120 of Figure 5 shows the performance as expected in terms of the Es / N0 required for a BLER of 10"1 as a function of the time delay between the uplink time interval and the downlink time interval. The delay is expressed by the number of time slots, which is the strategy of the complex symbol, Figure 5 shows that, when the gain / interference uncertainties are ignored, the operation of the combined system is almost identical to that of the Weighted open circuit system The combined system exceeds the performance of the closed loop system for all delays.

In the presence of gain and interference uncertainties, the level of energy transmitted from the open-circuit system is either too high or too low of the nominal value. In graph 122 of Figure 6, a gain uncertainty of -2 db was used. Figure 6 shows the BLER as a function of the delay. The initial reference SIR0BJECTIVE for each system was adjusted to its corresponding nominal value, obtained from Figure 5, in order to achieve a BLER of 10"1. Figure 6 shows that, in the presence of gain uncertainty, the systems of combined and closed circuit achieve the desired BLER.The operation of the weighted open circuit system is severely degraded.

Claims (26)

1. A method to control the levels of transmission energy in a simultaneous two-way time division communication system, of extended spectrum, having frames with time intervals for communication, the reception, in a first communication station, of the communications coming from of a second communication station, and the determination of an error ratio of the received communications, the production of objective adjustments as necessary, based, in part, on the proportion of errors, the transmission of a first communication having a transmit power level in a first time interval, and target settings from the first communication station, receiving the target and first communication settings in the second communication station, and measuring a power level of the first communication as received, determining an estimate of propagation loss based on, part, in the first received communication power level, the method is characterized by: adjusting a transmission energy level for a second communication in a second time interval from the second station to the first station, based, in part, in the estimate of propagation loss weighted by a first factor, an estimate of long-term propagation loss weighted by a second factor, and a target level adjusted by the objective adjustments, where the first and second factors are a function of a temporary separation of the first and second time intervals.

2. The method according to claim 1, further characterized in that the target level is a ratio of target signal to interference.

3. The method according to claim 2, further characterized in that the adjustments of the ratio of target signal to interference are limited to a maximum and minimum value.

4. The method according to claim 2, further characterized in that each objective adjustment is in a range of 0.25 decibels to 4 decibels.

5. The method according to claim 2, characterized in that: an objective setting that increases the ratio of target signal to interference is SIRINC; an objective setting that decreases the ratio of target signal to interference is SIRDEc an objective bit error ratio is BLEROBJECTIVE 'and SIRDEC is determined by SIRDEC = SIRINC x BLERQBJECTIVE / (I? LERQBJECTIVE) •

6. The method according to claim 5, further characterized in that the BLEROBJECTIVE is in the range of 1 to 10%.

7. The method according to claim 1, further characterized in that: if the error ratio exceeds a higher threshold or is below a lower threshold, an objective adjustment is transmitted; and if the error ratio is between the upper and lower threshold, the objective adjustment is not transmitted.

8. The method according to claim 7, further characterized in that the objective settings that increase the target level are transmitted as soon as an error count exceeds a higher threshold.

9. The method according to claim 1, further characterized in that: a quality, a, of the propagation loss estimate is determined based, in part, on a number of time intervals D between the first and second time intervals; and where the first factor is a and the second factor is l-a.

10. The method according to claim 9, further characterized in that a maximum time interval delay is Dma? and the determined quality, a, is determined by: a = l- (D-l) / (Dmax-l).

11. The method according to claim 9, further characterized in that a delay of the maximum allowed time interval is Dmax-allowed And the determined quality, is a, is determined by: a = ma x. { 1 - (D- l) / (Dmax-perm? T? Dol), 0} .

12. The method according to claim 1, further characterized in that the transmission energy level compensates for differences in the uplink and downlink gains.

13. The method according to claim 1, further characterized in that the first station is a base station and the second station is a user equipment.

14. The method according to claim 1, further characterized in that the first station is a user equipment and the second station is a base station.

15. A simultaneous bilateral time division, extended spectrum communication system having a first and a second communication station, the system uses frames with time intervals for communication, the first station receives the communications from the second communication station, and determines an error rate of the received communications, producing objective adjustments as necessary, based, in part, on the error rate, and transmitting a first communication having a transmit power level in a first time interval, and the target settings, the second station receives the objective settings and the first communication, and measures an energy level of the first communication as received, and determines an estimate of the propagation loss, based, in part, on the first communication energy level received, measured, the system is characterized because: the second station purchased nde: means for adjusting a transmission energy level for a second communication in a second time interval from the second station to the first station, based, in part, on the combination of the propagation loss estimate weighted by a first factor , an estimate of long-term propagation loss weighted by a second factor, and a target level adjusted by the objective settings, wherein the first and second factors are a function of a temporal separation of the first and second time intervals.

16. The system according to claim 15, further characterized in that the target level is a ratio of target signal to interference.

17. The system according to claim 16, further characterized in that the adjustments to the ratio of target signal to interference are limited to a maximum and minimum value.

18. The system according to claim 15, further characterized in that each objective setting is in a range of 0.25 decibels to 4 decibels.

19. The system according to claim 15, further characterized in that: if the error rate exceeds an upper threshold or is below a lower threshold, an objective adjustment is transmitted; and if the error ratio is between the upper threshold and the lower threshold, the objective adjustment is not transmitted.

20. The system according to claim 19, further characterized in that the objective settings that increase the target level are transmitted as soon as the error count exceeds a higher threshold.

21. The system according to claim 15, further characterized in that: the second station further comprises means for determining a quality, a, of the estimate of propagation loss, based, in part, on a number of timeslots D, between the first and second time intervals; and the first factor is a and the second factor is l-a.

22. The system according to claim 21, further characterized in that a maximum time interval delay is Dmax and the determined quality, a, is determined by: a = 1- (D- l) / (Dmax-l).

2. 3 . The system according to claim 21, further characterized in that a maximum allowed time interval delay is Dmax-Allowed and the determined quality a, is ..determined by: a = max. { 1 - (D- l) / (Dmax-perm? T a.doA), 0} .

24. The system according to claim 15, further characterized in that the adjusted transmit power level compensates for the differences in the uplink and downlink gains.

25. The system according to claim 15, further characterized in that the first station is a base station and the second station is a user equipment.

26. The system according to claim 15, further characterized in that the first station is a user equipment and the second station is a base station.