MX2008010458A - Methods of reverse link power control - Google Patents

Abstract

Methods of reverse link power control are provided. In a first example reverse link power control process, a signal-to-interference+noise (SINR) is measured for a plurality of mobile stations (S605). A power control adjustment is determined for each of the mobile stations based on the measured SINR for the mobile station and a fixed target SINR, the fixed target SINR being used in the determining step for each mobile station and sending the power control adjustments to the mobile stations (S610). In a second example reverse link power control process, one or more signals are transmitted to a base station (S405). A power control adjustment indicator indicating an adjustment to a transmission power level isreceived (S415). The received power control adjustment is determined based on a measured signal-to-interference+noise ratio (SINR) for the one or more transmitted signals and a fixed target SINR threshold, the fixed target SINR threshold being used for power control adjustment of a plurality of mobile stations (S410).

Description

INVERSE LINK ENERGY CONTROL METHODS FIELD OF THE INVENTION The exemplary embodiments of the present invention relate in general to communication systems and, more particularly, to wireless communication systems.

BACKGROUND OF THE INVENTION Figure 1 illustrates a Code Division Multiple Access (CDMA) 100, conventional. The CDMA system includes a plurality of user equipment (UEs) 105 in communication with one or more Service Nodes B 120/125 over an air interconnection. The plurality of Nodes B are connected to a radio network controller (RNC) 130 with a wired interconnection. Alternatively, while not shown in Figure 1, the functionality of the RNC 130 and the Node B 120/125 (alternatively referred to as "base stations") may be collapsed into a simple entity referred to as a "base station router". The RNC 130 accesses an Internet 160 through an entry support node (GSN) 150 and / or accesses a public switched telephone network (PSTN) 170 through of a mobile switching center (MSC, by REF.: 194781) 140. With reference to Figure 1, in the CDMA 100 system, an energy control mechanism is typically used to minimize energy consumption. energy and interference, while maintaining a desired level of functioning. Conventionally, this energy control mechanism is implemented with two power control loops. The first energy control loop (often referred to as an "internal" or "internal loop" energy control loop) adjusts the transmit power to each mobile station or UE 105/110, such that the signal quality of the the transmission received at the UE receiver (eg, as measured by a signal-to-noise ratio) is maintained at a target signal to interference + noise (SINR) ratio, or target Eb / N0. The target SINR or Eb / N0, where Eb is the energy per bit of information, and N0 is the energy spectral density of the interference observed by the receiver, is often referred to as the energy control set point, or threshold. The second power control loop (often referred to as an "external" or "external loop" energy control loop) adjusts the threshold such that the desired level of operation is maintained, for example, as measured by a speed of particular target block errors (BLER), frame error ratio (FER), or bit error rate (BER) for example. For example, for the control of link power (eg, forward link or reverse link), the internal loop compares a measured SINR or E / 0 of the received signal to the target SINR or target threshold. The SINR of the received signal is periodically measured, for example, at an interval of 1.25 milliseconds (ms). If the measured SINR or Eb / N0 is smaller than the threshold, there may be too many coding errors when the receiver is decoding frames or structures of a received transmission, such that the FER is outside an acceptable range (for example, too high). ). Consequently, the receiver asks for an increase in the energy over the link. If the measured SINR or Eb / N0 is larger than the threshold, the receiver asks for a decrease in the energy on the link. Here, the decoded transmission may contain few or zero errors, so the system may be too efficient (the FER is well below the acceptable range) and the transmission energy is being wasted. The outer loop surrounds the inner loop and operates at a much lower speed than the internal loop, such as 20 ms intervals, for example. The external loop maintains the quality of the service (QoS, for its acronym in English) of the link. The external loop establishes and updates the SINR threshold, which responds to changing channel / ambient conditions. The external loop estimates the quality of the link, and if the quality is too poor, the external loop increases the threshold accordingly. Alternatively, if the link quality is too good (for example, an FER lower than an objective FER of approximately 1% of transmissions, higher for data transmissions), the external loop readjusts the threshold so as not to unduly waste the resources of the system. In view of this, the target SINR is adaptive. And because this process is performed for each link, each receiver has its own adaptive target SINR such that the target SINR of different receivers (eg, UE receivers) differ. Figure 2 illustrates a conventional internal loop CDMA reverse link energy control process. The process of Figure 2 is described below as being performed with respect to the reverse link from UE 105 to Node B 120. However, it is understood that the process of Figure 2 is representative of a reverse link power control CDMA, conventional, between any UE in connection with any Node B. With reference to Figure 2, in the internal loop, Node B (for example, Node B 120) measures the SINR for the pilot transmissions received from a UE (for example, UE 105) in step S105. The measured SINR measurement (step S105) is either a pre- or post-interference cancellation measurement (IC). In one example, if the measurement of the pilot SINR is performed with post-interference cancellation, the Node B 120 measures the pilot SINR before the interference cancellation, and then measures the ratio of residual interference to total interference after the cancellation of the interference. the interference. The proportion of these two quantities is a measure of the post-interference cancellation SINR. The Node B 120 compares the measured pilot SINR with an adaptive target SINR in step S110. The objective of the adaptive SINR is previously established by the external loop in the RNC 130, to satisfy a level of Quality of Service (QoS), reflected by a proportion of errors in packets, expected (PER, for its acronym in English) or FER, for each served UE (for example, UE 105, 120, etc.). The objective of adaptive SINR is not the only factor that affects the QoS, however, if the adaptive SINR is established with a consideration of other such factors, to more precisely tune to the desired level of QoS. For example, another factor that potentially affects the QoS is a ratio of traffic to pilot (TPR) in the UE 105. The TPR in the UE 105 is set, and is not "adapted" as described above. with respect to adaptive target SINR. Here, the "fixed" TPR means that, for a given transfer rate, the TPR is adjusted to a constant value and does not change. The Node B 120 sends a transmit power control (TPC) bit to the UE 105 in step S115. A bit of TPC is a simple bit-binary indicator, which is set to a first logical level (eg, a higher logical level or "1") to instruct a UE (eg, UE 105) to increase the transmit power for a fixed amount, and a second logic level (eg, a lower logic level or "0") for instructing a UE (e.g., UE 105) to decrease the transmit power by the fixed amount. In one example, if the comparison of step S110 indicates that the measured pilot SINR is smaller than the target pilot SINR, the Node B 120 sends a bit of TPC having the first logical level (eg, a higher logic level or ""). 1") to the UE 105. Otherwise, the Node B 120 sends a bit of TPC having the second logical level (eg, a lower logical level or" 0") to the UE 105. After the Node B 120 sends the TPC bit to UE 105 in step S115, the process returns to step S105. In a further example, the frequency at which the Node B 120 measures (step S105) the pilot SINR, compares the measured pilot SINR with the adaptive target SINR (step S110) and sends the TPC bits (step S115) may be based on a desired "narrowing" of the energy control as It is determined by a systems engineer.

While the process of Figure 2 is being performed at Node B 120, in the external loop, RNC 130 periodically determines whether or not to adjust the adaptive target SINR, based on an analysis of the internal loop communications. This determination may be based on a number of criteria. For example, the RNC 130 decreases the adaptive target SINR if the PER or the FER is relatively low (for example, very few non-acknowledgments (NACK) are sent to the UE 105 indicating the failed transmissions) to satisfy a given level of QoS. In yet another example, the RNC 130 increases the adaptive target SINR if the PER is relatively high (for example, too many NACKs are being sent to the UE 105) to satisfy a given level of QoS. The RNC 130 then updates the adaptive target SINR used by Node B 120 in the process of Figure 2, according to the determined setting.

BRIEF DESCRIPTION OF THE INVENTION An exemplary embodiment of the present invention is directed to a method for controlling the reverse link transmission energy in a wireless communication network, including the measurement of a signal to interference + noise (SINR) ratio for a plurality of mobile stations, determining an energy control setting for each of the mobile stations, based on the measured SINR for the mobile station and the fixed target SINR, the fixed target SINR that is used in the determination step for each mobile station and sending power control settings to mobile stations. Another exemplary embodiment of the present invention is directed to a method for controlling the reverse link transmission energy in a wireless communication network, including the transmission of one or more signals to a base station, and receiving a control adjustment indicator of energy indicating an adjustment to a transmit power level, the received power control setting that has been determined based on a measured ratio of signal to interference + noise (SINR) for one or more transmitted signals and a SINR threshold fixed target, the fixed target SINR threshold that is used for the power control adjustment of a plurality of mobile stations.

BRIEF DESCRIPTION OF THE FIGURES The present invention will be more fully understood from the detailed description given below, and the accompanying figures which are given by way of illustration only, wherein like reference numbers designate corresponding parts in the various figures, and where: Figure 1 illustrates a conventional Code Division Multiple Access (CDMA) system. Figure 2 illustrates a conventional internal loop, CDMA reverse link energy control process. Figure 3 illustrates a CDMA reverse link energy control process, according to an exemplary embodiment of the present invention. Figure 4 illustrates a reverse link energy control process according to another exemplary embodiment of the present invention. Figure 5 illustrates a process for establishing a maximum transmission power per chip threshold for the transmissions of a mobile station according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION CDMA Inverse Link Energy Control A CDMA reverse link energy control process according to an exemplary embodiment of the present invention will be described below with respect to the conventional CDMA 100 system of Figure 1. More specifically, the mode will be described below as it is done with respect to the reverse link from UE 105 to Node B 120. However, it is understood that the embodiment may also be representative of the CDMA reverse link energy control between any UE in connection with any Node B. Furthermore, it will be appreciated that the processes of the present invention are not limited to the CDMA system of Figure 1 In the external loop, the RNC 130 selects a fixed target SINR or Eb / N0. As will be described below, the fixed target SINR is set for all UEs within the 100 CDMA system, and is used in the internal loop to evaluate the pilot SINRs measured in order to determine whether or not energy adjustments should be made of transmission. In one example, the fixed target SINR can be adjusted in conjunction with an initial ratio of traffic to pilot or TPR to maintain the proportions or error rates of CDMA control channels, expected below an error rate threshold. The error rates (a frame error rate (FER), a packet error rate (PER), etc.) reflect a Quality of Service (QoS) provided to the UE 105. As discussed in the Background section of the Invention, the target SINR and the TPR are two factors that potentially affect the QoS for the UE 105. Here, the RNC 130 adjusts the fixed target SINR and the TPRs based on the off-line link level curves for each UE served, conservatively, such that UEs, including UE 105, are very likely to reach a threshold QoS level. The adjustment of the "initial" values for the target SINR and the TPRs is well known in the art. However, while conventional internal and external loops and external loop power control mechanisms adjust the SINR objective to satisfy a QoS level while maintaining the TPR at a constant level at given speeds for all UEs, as will be described below, an exemplary embodiment of the present invention is directed to maintaining the target SINR at a constant level, while adapting the TPR for each served UE. The internal loop energy control performed in, for example, a Node B such as Node B 120, is illustrated in Figure 3. As shown, Node B 120 measures an SINR for a pilot signal received from UE 105 in step S405. The measured SINR measurement (step S405) is either a pre- or post-interference cancellation measurement (IC). In one example, if the pilot SINR measurement is performed with post-interference cancellation, the Node B 120 measures the pilot SINR before the interference cancellation, and then measures the ratio of residual interference to total interference after the interference cancellation . The proportion of these two quantities is a measure of the post-interference cancellation SINR. The Node B 120 compares the measured pilot SINR with the fixed target SINR in step S410. The Node B 120 sends a TPC transmission power control bit to the UE 105 in step S415. The TPC bit is a simple bit binary indicator that is set to a first logical level (eg, a higher logical level or "1") to instruct a UE (eg, UE 105) to increase the power of transmission by a fixed amount, and a second logic level (eg, a lower logic level or "0") for instructing a UE (eg, UE 105) to decrease the transmit power by the fixed amount. In one example, if the comparison of step S410 indicates that the measured pilot SINR is less than the fixed target SINR, the Node B 120 sends a bit of TPC having the first logical level (eg, a higher logic level or ""). 1") to the UE 105. Otherwise, the Node B 120 sends a TPC bit having the second logic level (eg, a lower logic level or" 0") to the UE 105. In a further example, the frequency a which the Node B 120 measures (step S405), compares the measured pilot SINR with the fixed target SINR (step S410) and sends the TPC bit (step S415) may be based on a desired "narrowing" of the energy control as is determined by a systems engineer. Figure 4 illustrates a CDMA reverse link energy control process, according to another exemplary embodiment of the present invention. The process of Figure 4 illustrates the steps performed in, for example, the UE 105. In one example, the UE 105 can be served by the Node B 120 operating in accordance with the process of Figure 3. As shown in FIG. Figure 4, in step S500, UE 105 establishes communication with Node B 120 using well-known methods. While the data is being transferred between the UE 105 and the Node B 120, the Node B 120 will periodically send acknowledgments (ACK) and not ACK (NACK) to the UE 105 to indicate successful or unsuccessful transmissions from the UE 105. Transmissions CDMA's typically include a pilot channel, a plurality of control channels (e.g., to send channel quality indicators (CQIs), etc.) and a plurality of traffic channels. The plurality of control channels and the pilot channel typically do not receive error feedback (e.g., ACK / NACK). Rather, error feedback is typically isolated to CDMA traffic channels. Accordingly, since error feedback for the control channels is not provided under the current CDMA protocols, a conservative proportion of initial to pilot traffic (TPR) is adjusted in step S505, such that the error proportions for the plurality Control channels are expected to remain below an error rate threshold. The TPR multiplied by the energy level of the pilot signal of the UE 105 is the energy level for the transmissions over the EU 105 traffic channels. As discussed above, the initial TPR can be adjusted in conjunction with the target SINR to levels Conservatives, in order to maintain the error rates of control channel, below the error rate threshold. As discussed in the Background of the Invention section, the target SINR and the TPR are two factors that potentially affect the QoS for the UE 105. The RNC 130 adjusts the fixed target SINR and the initial TPRs for each UE served, so conservative, such that the UEs, including the UE 105, are very likely to reach a threshold QoS level, as reflected by FER, PER, etc. In one example, the initial TPR may be the "best wish" of the system designer for a good starting point for an adaptive TPR. The value of the initial TPR is not critical to the operation of the process in Figure 4 because, as will be discussed later, the initial TPR is updated or adjusted to reflect and respond to the actual operating conditions. UE 105 receives ACK / NACK from Node B 120 in response to data packets transmitted to Node B 120 in step S510. Based on the ACK / NACK received, the UE 105 determines whether the current, effective error rate is below the error rate threshold in step S515. As discussed above, the initial TPR is adjusted (step S505), based on an expected error rate. After this, the TPR is adjusted by the UE 105 in step S515 based on the actual operating conditions. If the actual operating conditions indicate that the speed or proportion of errors is above the error rate threshold (for example, worse than expected), the TPR is increased (for example, by a first fixed amount) in step 515. For example, if the UE 105 attempts to transmit a given data packet no more times without an ACK reception, the TPR is incremented by the first fixed amount. Alternatively, if the actual operating conditions indicate that the error rate is below the error rate threshold (e.g., better than expected), the TPR is decreased (e.g., by a second fixed amount) in step S515 For example, if a data packet is transmitted by UE 105 and recognized within n attempts, the TPR is decreased by the second fixed amount. For example, if the requirement is that the error rate after 4 attempts of HARQ is x = l%, then TPR_pasobaj or / TPR_pasoalto = x / (l-x) is established. In this case, whenever a packet succeeds in less than 4 attempts, the TPR is decreased by the TPR_pasobaj or, and if it fails after 4 attempts, the TPR is increased by TPR_pasoalto. However, it is understood that the transmission energy levels adjusted by the TPR may have physical constraints and constraints on computer hardware (software). A physical constraint of the transmit power level set by the TPR is an effective physical transmission threshold (eg, a maximum transmit power level for the UE 105 at its highest power settings). A software constraint is a maximum artificial transmission power level (for example, hereinafter referred to as "maximum transmission power threshold per chip") typically adjusted by the external loop to reduce the interference of the entire system by not allowing that all users transmit to their highest possible levels. An example of setting the maximum transmission power threshold per chip is described below with respect to Figure 5. After the TPR is adjusted in step S515, the process returns to step S510 and waits for the additional ACK / NACK from Node B 120. In another exemplary embodiment of the present invention, with reference to Figure 4, the continuous adjustment of the TPR in step S515 for the ARQ Hybrid Channels (HARQ) may allow an objective PER or QoS to achieve a threshold given after a number of transmissions based on the ACK / NACK received in step S510. In another exemplary embodiment of the present invention, with reference to Figure 4, if UE 105 is engaged in soft hands-free (for example, with Nodes B 120 and 125), UE 105 receives ACK / NACK over multiple legs ( for example, from multiple Node B) and the determination of the effective error rate in step S515 is with this based on ACK / NACK in a plurality of sectors. In this case, the TPR setting made in step S515 is based on the ACK / NACK received from Nodes B 120/125 involved in soft hands-free. Numerous advantages of the "fixed" target SINR as opposed to the conventional adaptive target SINR will be readily apparent to a person skilled in the art. For example, the objective update procedure of the SINR, conventionally performed in the external loop (for example, in RNC 130), does not need to be performed. With this, the numerous tables conventionally devoted to the SINR objective update procedures can be used for other purposes. Processing conventionally performed by the external loop or RNC 130 is downloaded onto the UE 105 in the exemplary embodiments of the present invention because the UE 105, when engaged in soft hands-free, uses the ACK / NACKs from all Nodes B 120/125 in its active group (for example, a group of Node Bs with which the UE 105 communicates during the soft hands-free to determine whether or not the TPR is set, in contrast to the external loop or RNC 130 it is determined whether whether or not the target SINR is adjusted While the exemplary CDMA reverse link energy control process was described as being implemented within the conventional CDMA system 100 of Figure 1, the link energy control process CDMA inverse can be applied alternatively in any system capable of operating in accordance with CDMA protocols, such as a hybrid orthogonal frequency division (OFDMA) / CDMA multiple access system. Further example, while not being described in this application, maintaining the fixed target SINR can simplify the control of the OFDMA reverse link power because the pilot SINR measured from CDMA (eg, which can be used in an OFDMA reverse link energy control process) can be predicted more accurately in the UE 105. In another example, the process of controlling the reverse link energy of OFDMA, described above , can be employed in an interference cancellation receiver because the TPRs in the UEs (eg, UE 105) can be adjusted in step S520 to explain the interference in a plurality of traffic channels.

Maximum Mobile Station Transmission Energy An example of the establishment of a maximum energy threshold per chip for the UE 105 transmissions will now be described. In one example, the UEs located near the edges or boundaries of the cells (eg, between Node B 120 and Node B 125) have more effect on interference from the neighboring cell compared to UEs located in close proximity to a Service Node B (for example, near a central position of the cell). If control is not maintained on the maximum energy with which a given UE can transmit, the interference of the entire system can be increased. The following example of setting a maximum level per chip or maximum transmission power level for a UE within the conventional CDMA 100 system is given as a function of the position of the UE with respect to a plurality of cells. Further, while the following exemplary embodiments are described with respect to UE 105 having Node B 120 as a Service Node B and Node B 125 as a neighboring Node B, this particular arrangement is given for exemplary purposes only, and will be It is readily apparent that the process of controlling the maximum transmit power per chip given below can alternatively be applied to any UE within the CDMA 100 system. Each of the Node Bs (e.g., Nodes B 120, 125, etc.) within the CDMA 100 system periodically measures an amount of external cell interference, received (for example, interference from cells different from the cell itself of Node B). Each of the Nodes B compares the external cell interference, measured, with an external cell interference threshold Ioumbrai-In one example, the RNC 130 can establish the external cell interference threshold Ioum rai for the Nodes B 120/125 . Each of the k Nodes B transmits (for example, to all UEs within the range, such as UE 105) an Interference Activity Bit (IAB) based on the comparison. In an example, with reference to a Node B "p", if the comparison indicates that the measured external cell interference is greater than the external cell interference threshold lOumbrai then IAB (p) = l, where the Node B p is representative of one of the Nodes B within the CDMA 100 system. Otherwise, if the comparison indicates that the external measured cell interference is no greater than the external cell interference threshold lOumbrai, then IAB (p) = 0 . It is understood that IABs can be transmitted from one or more Nodes B at one time, such that multiple IABs can be received by an UE within the CDMA 100 system, partly based on the position of the UE relative to the Nodes. B neighbors or service within the CDMA 100 system. A process of adjusting the transmit power threshold per chip, performed in the UEs within the CDMA 100 system, which also takes into account the IABs transmitted by the Node B, will now be described next with respect to a representative UE 105 in Figure 5. Figure 5 illustrates a process of establishing a maximum transmission energy threshold per chip for transmissions of a UE according to an exemplary embodiment of the present invention. The exemplary embodiment of Figure 5 is described below with respect to a representative UE (e.g., UE 105) and k Nodes B (e.g., Node B 120, 125, etc.) within the conventional CDMA 100 system, wherein k is an integer greater than or equal to 1. The steps illustrated in Figure 5 and described below are performed in, for example, UE 105 of Figure 1. The representative UE 105 is not necessarily in active communication with more than one of the k Nodes B (for example, although this may be, such as in the soft hands-free mode, but the representative UE 105 is capable of "listening to" or receiving signals from all k Node Bs. consequence, it will be appreciated that the number k may vary based on the position of the UE 105 within the CDMA 100 system. For example, if the UE 105 is in very close proximity to a serving Node B such as the Node B 120, k typically is equal to 1. As the UE 105 approaches more than one edge of a cell, k is typically greater than 1. In the exemplary embodiment of Figure 5, in step S600, the maximum transmission power threshold per chip of the UE 105 which is served by the Node B 120, is initialized, by the UE 105, to Pmax (1) (G (d)), d = l, k Equation 3 where Pmax (l) denotes a maximum energy for an initial period of time, Ioumbrai denotes an external cell interference threshold (for example, an amount of external cell interference that can be tolerated), and G (d) denotes a average channel gain from UE 105 to a dth Node B between k Nodes B, where d is an integer from 1 to k. In one example, the measurements of G (d) are based on the SINR measurements on the common pilot and the preamble, and the external cell interference threshold lOum rai is determined by a design engineer. The UE 105 receives the IABs (discussed above before Figure 5) from each of the k Nodes B in step 605 and determines whether or not in step S610 an adjustment is required for the maximum transmission power threshold per chip . If step S610 determines that an adjustment is necessary, an energy setting for the UE 305 in step S615 is calculated. Otherwise, the process returns to step S605. In step S615, the UE 105 establishes a cuvette of indications for the transmission power resource called PCbucket (t), which denotes the instantaneous updated value of the transmission power resource based on the received IABs, expressed as Pcbucket (t) = PCbucket (t-1) + AP Low Equation 4 if any of the IABs received by the UE 105 are set to "1", where APbaj0 = w * max (G (y)), where y denotes and Nodes B among the k Nodes B that are sending the IAB equal to "1" at time t, and w is a fixed weighting factor determined by a design engineer.

PCbucket (t) is alternatively expressed as PCbucket (t) = PCbucket (t-1) + APaito Equation 5 if all the IABs received by the UE 105 are set to "0", where "t" denotes a current period of time and "t-1" denotes a previous period of time, and APait0 is expressed by APalt0 = (x / (1-x)) APbaj0 where x is equal to the probability that the external cell interference measured by a given Node B is greater than the external cell interference threshold Ioumbrai- In one example, the probability "x" is based on a coverage requirement for the given Node B (for example, Node B 120). In a further example, the probability "x" is determined during the deployment or installation of the CDMA 100 system. Pcbucket () is an averaged version of PCbucket (t), and is expressed as Pcbucket (t-1) + Pcbucket (t) -Pmax (t-1) Equation 6 Pmax (t) evaluates a Pmax (t) Omin (Pmax (t-1), Pcbucket (t)) Equation 7 if a new encoder packet is programmed for transmission from UE 105 to Node B 120, and Pmax (t) = PCbucket (t) "Pmargen Equation 8 if a new encoder packet is not programmed for transmission, where Pmargen is a displacement value that is greater than or equal to 0, to ensure that the bin does not empty during transmission of the encoder packet. In one example, the data rate for the new encoder packet is selected such that Pmax (t) is set at a sufficient energy level, to achieve a threshold level of spectral efficiency. Once the maximum transmit power threshold per chip Pmax (t) is set according to one of Equations 7 and 8 in step S615, the process returns to step S605. Accordingly, with the exemplary methodology described above with respect to Figure 5, a person skilled in the art will appreciate that the UEs closest to a greater number of Node Bs (eg, farther from a Service Node B and more near the edges of the cell) adjust the maximum transmit power threshold per chip with larger steps, while the closest UEs in proximity to the serving Node B react more slowly to the IAB bits. The combination of the pilot reference energy (Po (t)) and the maximum allowed data / pilot energy per chip can be used in the computation of the spectral efficiency as required by the UE. The exemplary embodiments of the present invention having been described in this way, it will be obvious that it can be varied in many ways. For example, while what has been described above with respect to a conventional CDMA wireless communication system, it will be appreciated that the CDMA reverse link energy control methodology described above, can alternatively be applied to any wireless communication system operating in accordance with CDMA (for example, a hybrid OFDMA / CDMA system).

Furthermore, it is understood that a Node B and a UE can alternatively be referred to as a base station (BS) and a mobile station (MS) or mobile unit (MU), respectively. Such variations are not considered to be a departure from the exemplary embodiments of the invention, and all such modifications are intended to be included within the scope of the invention. It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (10)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A method for controlling the reverse link transmission energy in a wireless communication network, characterized in that it comprises: measuring a ratio of signal to interference + noise (SINR) for a plurality of mobile stations; determining an energy control setting for each of the mobile stations based on the measured SINR for the mobile station and a fixed target SINR, the fixed target SINR is used in the determination step for each mobile station; and the sending of energy control settings to mobile stations. The method according to claim 1, characterized in that it further comprises: the selection of the fixed target SINR to thus maintain the error rates or proportions on a communication channel in the wireless communication network, below a threshold of error speed. The method according to claim 1, characterized in that the determination step compares the measured SINR with the fixed target SINR, wherein each of the power control settings instructs the mobile station to increase a power level of transmission if the measured SINR is less than the fixed target SINR and instructs the mobile station to decrease the transmission power level if the measured SINR is no less than the fixed target SINR. The method according to claim 1, characterized in that it further comprises: the measurement of the external cell interference; and transmitting a first interference indicating signal, which indicates whether the measured external cell interference exceeds or not an external cell interference threshold. A method for controlling the reverse link transmission energy in a wireless communication network, characterized in that it comprises: transmitting one or more signals to a base station; and receiving an energy control adjustment indicator indicating an adjustment to a transmission power level, the energy control adjustment received having been determined, based on a measured ratio of signal to interference + noise (SINR) for a or more signals transmitted, and a fixed target SINR threshold, the fixed target SINR threshold is used for the power control setting of a plurality of mobile stations. 6. The method according to claim 5, characterized in that it further comprises: the adjustment of the transmission energy level according to the energy control adjustment indicator received. The method according to claim 5, characterized in that it further comprises: the reception of a plurality of interference indicating signals, coming from different base stations; and determining whether to adjust a maximum transmission power threshold based on the plurality of interfering indicator signals, the maximum transmission energy threshold that indicates a maximum allowable transmission energy level below which the transmissions are constrained. The method according to claim 7, characterized in that it further comprises: the increase of the maximum transmission energy threshold and at least one of the plurality of interference indicating signals indicates an external interference exceeding an external cell interference threshold; and decreasing the maximum transmit power threshold if the plurality of interference indicator signals do not include at least one interfering signal indicating an external cell interference that exceeds the external cell interference threshold. 9. The method of compliance with the claim 8, characterized in that the step of increase increases the threshold of maximum transmission energy by a first fixed amount and the step of decrease decreases the threshold of maximum transmission energy by a second fixed amount. 10. The method of compliance with the claim 9, characterized in that the first fixed amount is expressed by (1-) 1 * P where Paito is the first fixed quantity, x is a probability that the measured external cell interference will exceed the external cell interference threshold, and P is the second fixed amount, and the second fixed amount P below is expressed by P low = w * (max [G (d)) where max (G (d)) denotes an average or maximum channel gain between channel gains average for the d base stations, the base stations d transmit interfering signal d indicating an interference of (external cell exceeding the external cell interference threshold.