CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -1- METHOD AND SYSTEM FOR MONITORING POWER OUTPUT IN TRANSCEIVERS BACKGROUNID The present invention relates generally to methods and systems for radiocommunications and, more particularly, to such systems in which communication quality is monitored and connections can be handed over from one channel or base station to another based on monitored quality. The cellular telephone industry has made jphenomenal strides in commercial operations in the United States as well as the rest of the world. Growth in major metropolitan areas has far exceeded expectations and is rapidly outstripping system capacity. If this trend continues, the effects of this industry's growth will soon reach even the smallest markets. Innovative soluiaons are required to meet these increasing capacity needs as well as maintain higli quality service and avoid rising przces. In cellular systems, the capability is typicaaly provided to transfer handling of a connection between, for example, a mobile station and a serving base station to another, neighboring base station, as the mobile station changes its position and so moves out of the coverage area of one base station and into the coverage area of another base station. This type of handoff is commonly referred to as an "intercell" handoff as the coverage areas associated with base stations are commonly referred to as "cells". Depending upoti the quality of the current channel, it may also be desirable to transfer a connection from one channel of the base station to another channel supported by the same base station, which handoffs are commonly referred to as "intracell" handoffs. To smoothly complete a handoff, the network controlling the base stations first determines, for each mobile station, whether the need for handoff from its currently serving base station is imminent and secondly determines to which new base station (or channel) handoff should be effected. In making the former CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -2- decision, the radiocommunication system monitors the quality of the mobile station's current connection. In making the latter decision it is desirable that the network controller know either how well each neighboring base station can receive signals from a mobile station in question, how vvell the mobile station in question can receive signals from each neighboring base station, or both. Monitoring signalling associated with a serving base station and neighboring base stations typically involves making signal strength measurements, which measurements can be made in a variety of ways depending, for example, on the type of access methodology employed by the radiocommunication system. Many existing radiocommunication systems are based on an access method known as Frequency Division Multiple Access (FDMA), in which each mobile station transmits on a unique frequency within it:s current base station area. The mobile station is thus unaware of signals on other frequencies from surrounding base stations. In FDMA systems it is typically considered too costly to equip mobile stations with an extra receiver that could be used to scan other base station frequencies to determine their received signal sGrength. Instead, it is common for base stations to be equipped with a scanning receiver that searches for the signals of approaching mobile stations. When the base stations scan for the signal strength of mobile stations, the method could be termed base assisted handover (BAHO). The network then hands over a mobile station from a base station covering an area that the mobile is leaving to the base station that reports the best reception of the mobile station's signal. More recent cellular telephone standards employ Time Division Multiple Access.(TDMA) in which a fixed time period (e.g., 20 mS) on each pair of radio frequency links (one used in the direction from mobiie station to base station (uplink), the other used in the direction from base station to mobile station (downlink)) is divided into a number (e.g., 3) oi'short timeslots (e.g., 6.6 mS) that are cyclically used by different mobile stations. Thus, a firsL mobile station transmits in the first timeslot in each period, a second mobile station transmits in CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -3- the second timeslot in each period and so on. Likewise the base station transmits to one mobile station in the first timeslot, another mobile station in the second slot and so on. By offsetting the allocation of timeslots in the two communication directions, base to mobile (the downlink) and mobile to base (the uplink), it can be arranged that a first mobile transmits in the first -timeslot and receives in the second timeslot; a second mbile transmits in the second timeslot and receives in the third, while a third mobile transmits in the third timeslot and receives in the first timeslot. An advantage of this arrangement is that a mobile station does not need to transmit and receive simultaneously, which reduces disturbance. In the above three-timesiot example, each mobile station is active to transmit or receive in two of the three timeslots and is idle in the remaining timeslot. Therefore it is possible for TDMA mobile stations to use this idle time to receive signals from other base stations and measure their signal strength. Typicaily, such measurements are made on the control channels (or some type of other measurement channel) being broadcast by these base stations, rather than the traffic channels used to support circuit-switched or packet-switched connections. By reporting these signal strength measurements to the base station using a slow speed data channel multiplexed with the traific (e.g., voice), the network is informed about the base stations each mobile station can receive. The network can use this information to effect handoff to the preferred base station, and such a method is termed mobile assisted handover (MA130). For example, the system can compare the measured signal strengths associated with neighboring base stations to the signal strength at which the mobile; station is receiving transmissions from its serving base station. If a neighboring base station is received at a sufficiently higher signal strength (e.g., employing a hysteresis value to avoid a "ping-pong" handoff effect at cell borders), than the serving base station, then a handoff is performed. Systems providing MAHO can also have access to the base station measurements, and so are able to effect sinoother and more reliable CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -4- handovers because both uplink and downlink signal strengths are taken into account, instead of just uplink strengths in the case of BAHO. In yet another access technique, Code Division Multiple Access (CDMA), mobile stations can share the same frequency band but communications are distinguishable by virtue of unique spreading codes. Even in CDMA systems it is possible to measure a signal strength of pilot channels associated with a particular base station. The base station and/or mobile station can use this information to determine when a handover to another code, or another frequency band in multi- carrier CDMA, is desirable. As can be seen from the foregoing, a cor,nmon element in determining when a handoff is desirable involves the measurement and comparison of received signal strengths, and in particular measurements made on control channels of various neighboring base stations. However, there are several complicating factors relating to the output transmit powers of the trari.sceivers within base stations which reduce the accuracy of conventional handoff algoritbms. The actual output transmit power of a pairticular transceiver can vary from transceiver to transceiver within a base station for a number of different reasons. For example, problems or changes to components within a transceiver may cause its actual output transmit power to vary from an intended value. Other factors which may cause variances in actual output transmit power between transceivers involve different power settings which are intended to permit, for example, a network operator to have greater control over system operation. For example, control channels and traffic: channels are not always transmitted by base stations using the same transmit power. In some systems it is possible to transmit control channels at a higher power level than traffic channels in the same cell to ensure that the control inforniation contained in the control channels will be accurately received by the potentially large number of mobile stations that are listening thereto. To enable, for example, a network operator, to control a transmit power difference between con.trol channels and traffic channels a CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -5- power setting for traffic channels (PSVB) and a power setting for measurement channels (PSMB) can be provided. These two settings can also be combined into one differential power setting, e.g., PSVB-PSMB. The PSVB and PSM13 power settings (or differential power setting) are stored iin the mobile switching centers (MSCs) of radiocommunication systems for each base station, which base station typically includes a plurality of transceiver devices. In addition to the PSVB/PSMB power settings, network operators can also set the basic output power of each transceiver device individually. Like the PSVB/PSMB power settings, these individual traiisceiver power settings can also be stored in the MSC. From the foregoing, it wiil be apparent to those skilled in the art that the actual output transmit power of the transceiver devices may vary from an intended output tran.smit power for many reasons. The PSVB/PSMB setting for a base station may be incorrect. The individual transceiver power setting may be incorrect. One or more of the components involved in the transmit path of the transceiver may be malfunctioning, or any combination of these things could occur. Under any of these scenarios, the system may perceive a neighboring base station as being a better server for a particular mobile station when, in fact, its current serving base station is still superior or vic:e versa. For example, assume that a neighboring base station is selected as a better server due (at least in part) to the strength at which its control channel is received by a mobile station. Then, when the mobile station is assigned to a traffic channel that is transmitted using a different transceiver, the mobile station actually receives a relatively weak signal because the traffic channel transceiver is transmitting at a much lower power level tlm expected, e.g., due to a fault in the transceiver, because the PSVB / PSM13 setting(s) is incorrect, and/or because the individual power setting of that transceiver has been set incorrectly. If this occurs, then measurements taken subsequent to the handoff wiill indicate that a different base station is the best server and the mobile will be handed off again, which results in CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -6- poor call quality and is an inefficient use of resources. Conventionally, these problems associated variances between intended output transmit powers and actual output transmit powers of transceivers have been addressed empirically, i.e., generally by operators manuaUy observing cell performance. Accordingly, there is a need to develop enhanced techniques to monitor power outputs and power settings of transceivers in radiocommunication systems more accurately, so that processes, such as handoff, can be performed in an efficient way to avoid oscillating connections caused by the "ping-pong" effect described above. SIIldMA1-t'V: These, and other, problems, drawbacks, and limitations of conventional output power monitoring techniques, are overcome according to the present invention in which exemplary embodiments provide for a comparison between the signal strength of the measurement channel of a candidate base station and the signal strength of the traffic channel associated with that measurement channel. More specifically, the mobile station can measure the signal strength of the candidate base station prior to handoff and report that signal strength to its current base station. The base station can report the sigal strength of the measurement channel to the MSC in the handoff request. Then, when the mobile station is handed off to a traffic channel associated with tl~e new serving base station, i.e., based upon the earlier reported measurement channel's signal strength, the signal strength of the traffic channel will also be reported by the mobile station and forwarded to the MSC. The system can then create a statistic which tracks the difference between the measured control channel signal strength and the measured traffic channel signal strength, which statistic can then be used to either manually or automatically adjust the output power of a transceiver, a power setting, or both. A.lterna.tively, the statistic can be generated by measuring a received signal strength of the mobile station's original traffic channel prior to handoff and a CA 02356906 2007-08-01 -7- received signal strength of the mobile station's new traffic channel after a handoff. These signal strengths are compared in the system to identify output power variances. According to an aspect of the invention there is provided a method for monitoring output transmit power of transceivers in a radiocommunication system, said method comprising the steps of: measuring by a mobile station, a first received signal quality associated with a control channel being transmitted by a base station; measuring by the mobile station, a second received signal quality associated with a traffic channel being transmitted by said base station; determining a difference between said first and second received signal qualities; and using said difference to monitor an output power of a transceiver of said base station. According to another aspect of the invention there is provided a method for monitoring output transmit power of receivers. in a radiocommunication system comprising the steps of measuring a first received signal quality associated with a traffic channel being transmitted by a first base station; measuring a second received signal quality associated with a traffic channel being transmitted by a second base station; determining a difference between said first and second received signal qualities; and using said difference to monitor an output power of a transceiver of one or both of said first and second base stations; and, wherein measuring of one of said first received signal quality and said second received signal quality is preformed prior to a handoff, and measuring of the other of said first received signal quality and said second received signal quality is preformed after said handoff. According to a further aspect of the invention there is provided an apparatus for monitoring output transmit power of transceivers in a radiocommunication system, said apparatus comprising: a switch for coordinating the operation of said transceivers and storing parameters associated with controlling said output power of said transceivers; and a processor for: (a) receiving, from said switch, signal quality difference information associated with handoff, (b) processing said received signal quality difference information using at least one logic function, and (c) returning a changed value to at least one of said stored parameters. CA 02356906 2007-08-01 -7a- BRIEF DESCRIPTION OF THE DRAWINGS The foregoing, and other, objects, features and advantages of the present invention will be more readily understood upon reading the following detailed description in conjunction with the drawings in which: Figure 1 illustrates an exemplary cellular radiocommunication system; Figure 2 is a block diagram representation of an exemplary mobile station which can be used to implement the present invention; Figure 3 is a block diagram of a base station including a number of transceiver units whose power can be monitored according to exemplary embodiments of the present invention; Figures 4 and 5 are tables including exemplary accumulated delta statistics according to exemplary embodiments of the present invention; and Figure 6 depicts a processor which gathers and processes delta statistics from a radiocommunication switch. DETARED DESCRIPTION In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular circuits, circuit components, techniques, etc. in order to provide a thorough understanding of the invention. For example, various details are provided relating to exemplary modulation and transmitting techniques. However it wi11 be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -8- devices, and circuits are omitted so as not to obscure the description of the present invention with unnecessary details. Prior to describing the details of the present invention, an example of the construction of a cellular mobile radio system in which the present invention can be used is illustrated in Figure 1. Figure 1 is a schematic diagram illustrating ten cells, Cl to CIO. Normally, systems and methods according to the present invention would be implemented in a system cornprising many more cells than ten. For the purposes of this description, however, the system depicted in Figure 1 is considered to be an isolated region of a larger system. . For each cell Cl to C 10, there is a respective base station B 1 to B 10. The exemplary embodiment illustrated in Figure 1 shows base stations situated in the vicinity of respective cell centers and having omni-directional antennas. Those skilled in the art will readily appreciate that the base stations may be located in other areas of the cells and have other types of antennas, for example, in the vicinity of cell borders and having directional sector antennas or array antennas. Figure 1 also illustrates ten mobile stations Ml to M10, which are movable within a cell and from one cell to another cell. Again, methods and systems according to the present invention can be practiced with more or less than ten mobile stations. Also illustrated in Figure 1 is a mobile switching center (MSC). The MSC is connected to all ten base stations by cables (not all shown) and to a fixed public switching telephone network (PSTN, not shown) or simiiar network. The MSC routes calls to and from the base stations and coordinates the activities of the system. Cellular systems are assigned to a particular frequency band over which they can operate. This frequency band is allocated in units called channels to the cells in a particular area. Different access methodologies, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and hybrids thereof, renders the meaning of what CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -9- constitutes a "channel" to be different from systent to system, as will be appreciated by those skilled in the art. Nonetheless, as discussed above, the efficient use of the frequency spectrum is an important consideration in maximizing system capacity. Thus, it is not surprising that a number of different methodollogies have been adopted for allocating channels to the various cells and, more particularly, to assigning a channel for new connections occurring within each cell. Some of these methodologies allocate fixed sets of channels to each cell, while others allocate channels dynamically based on traffic densities and/or interference situations. In all of these methodologies, however, the system generally provides the capability to change channels when signal quality degrades to an unacceptable degree. For example, the system may determine that a handoff is needed based on periodic measurements of signal strength (and possibly other connection parameters) associated with the connection between the mobile station and its current serving base station. These measurements are typically reported to the system periodically by way of channel quality measurements (CQMs) transmitted by the mobile station to the base station. In one exemplary embodiment handoff decisions are made based on downlink signal strength of the serving (SSsmv) and the target (SSrõao) base stations as measured by the mobile station and reported to the land system, for example using the conventional Mobile Assisted F[andoff (MAHO) function mentioned above. Using the MAHO function, a mobiie station may be ordered by the system to measure and report signal strength (and possibly other) parameters associated with the signal transmitted by the base station to which it is connected, as well parameters associated with signals transmitted by one or more target (also referred to as "candidate") base stations. An exemplary embodiment of a mobile staition which can operate to perform MAHO measurements is illustrated in Figure 2. This block diagram has been simplified to illustrate only those components relevant to the measurement of CA 02356906 2001-06-26 ' WO 00/41337 PCT/SE99/02344 -10- downlink signal strength, however those skilled in the art will be well aware of the other major functional blocks associated with mobile stations. In Figure 2, incoming radio signals are received by transmitter/receiver TRX 100. The timing is synchronized to the received symbol sequence by microprocessor controller 130. The strength of the received signals are measuired by a signal strength measuring part 120, the value of which is then passed to inicroprocessor controller 130. The bit error rate (BER) of the received signal can also be determined as an indication of received signal quality as reflected by block 140. The mobile station will also have input/output devices, such as a keyboard and display 135, as well as a microphone and speaker unit (not shown), which enables information to be exchanged between the mobile station and the ibase station. When the mobile station receives a list of channel numbers and/or frequencies in a MAHO command, it will sequentially tune to each identified channel/frequency during one or more measurement intervals. For example, in a TDMA system the measurement intervals may be provided during idle time slots, i.e., during time slots when the mobile station is not transmitting or receiving over its currently assigned traffic channel. Once the mobile station has made the requested measurements, it will report them to the system which will then evaluate the various target base stations using a handoff' algorithm. Although simplified for the purposes of better illustrating the present invention, handoff algorithms according to the present invention can be represented as: SSz.ARG > SSseRv + Hyst (1) where: Hyst is a hysteresis value which is added to the signal strength of the serving base station to avoid oscillating handoffs. When the: inequality is true, then a handoff is justified to the target base station. . Otherwise, the system evaluates any other target base stations or maintains the current connection. Of course those skilled in CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -11- the art will appreciate that other factors, e.g., service availability, macro/microcell preference, etc. may also be considered in the handoff algorithm. Figure 3 illustrates a transceiver unit 400 which can be used, for example, as one of the cellular base stations B1..B10 illustrated in Figure 1. Therein, a plurality of radio transmitters 410 and radio receivers 420 are provided, each of which is adapted to handle an independent carrier frequency. These devices can be designed according to well known techniques, e.g., transmitters 410 may include amplifiers, upconverters, filters, analog-to-digittl converters, etc. and receivers 420 mayl include amplifiers, downconverters, filters, digital-to-analog converters, etc. These devices are controlled by, and pass information to and from, control unit 430 which includes a central processing unit (not shown), memory (not shown) and a signal processing device 440. Signal processing device 440 provides the necessary software functionality for processing both signals to be transmitted and signals that are received via transmitters 410 and receivers 420, respectively. For example, signal processing unit 440 can provide the signal encoding, modulation, scrambling and channel filtering fiuzctions, etc. for transmitted signals which may be necessary depending upon the channel configuration (e.g., access methodology, bandwidth, etc.) as will be appreciated by those skilled in the art. Likewise, signal processing circuitry 440 can aLso perform channel filtering, demodulation, decoding and descrambling tasks on received signals. The signal processing device 440 can be implemented, according to exemplary embodiments of the present invention, using a flexible ASIC approach which allows the signal processing functions to be selectively changed to accommodate the antenna arrangement and sigrLti processing desired by the network operator. The transceiver unit 400 may have any number and type of antema arrangement connected thereto. However, for the purposes of illustrating the present invention, transceiver unit 400 is connected to two directional sector antennas 450 and an antenna array 460 having N antenna lobes or elements. The antenna array 460 is supported by beamforming unit 470, which shapes and steers CA 02356906 2007-08-01 -12- the plurality of beams to achieve a desired coverage area. The beamforming unit 470 can comprise any conventional fixed beamformer, such as a Butler matrix. As illustrated in Figure 3, each of the sector antennas 450 and each element of the antenna array 460 can be connected to one or more respective radio transmitter(s) 410 and radio receiver(s) 420 through transmit switch 480 and receive switch 490, respectively. The switches 480 and 490 are used by the transceiver to selectively assign resources to various connections under the supervision of control unit 430. Radio base stations such as those illustrated in Figure 3 provide significant flexibility in operation. For example, the sector antennas 450 and antenna array 460 can be used to propagate different types of signals/channels to support radiocommunication service. In such an exemplary application, it may be desirable to have different values for PSVB and PSMB which introduces more possibility for output power anomalies and more reason to introduce a power monitoring scheme as will now be descn-bed. To better understand techniques for monitoring and controlling power settings and output transmit power according to exemplary embodiments of the present invention a specific, yet still illustrative, example will now be provided wherein a mobile station M5 in Figure 1 has recently moved such that the system's handoff algorithm has determined that a handoff is necessary from its current serving base station, e.g., base station B1, to a target base station, e.g., base station B3. For the purposes of this example, the following different measurement variables are defined: Ss,(Bl) is the signal strength measured by mobile station M5 on its traffic channel with base station B 1 prior to handoff; CA 02356906 2001-06-26 Wo 00/41337 PCT/SE99/02344 -13- Ss,(B1) is the signal strength measiired by mobile station M5 on a control channel (or measurement channel) transmitted by base station B 1; Ss,(B3) is the signal strength measured by mobile station M5 on its new traffic channel with base station B3 after the handoff; Ss,(B3) is the signal strength measured by mobile station M5 on a control channel (or measurement channel) transmitted by base station B3. According to exemplary embodiments of the present invention, the system monitors and controls power outputs and power settings of base station transceivers by creating statistics associated with mobile station's measurements before and after handoff. For example, using the variables defmed above, the system can create a statistic, Ssd (referred to herein as the "delta statistic"), by comparing the signal strength measured on the new base station's traffic channel after handoff Sst(B3) with the signal strength measured before the handoff on the cqntrol (measurement) channel of the new base station Ssr(B3). For this particular handoff in this particular exemplary embodiment, the statistic can be calculated as: SSd = Sst(B3) - SsjB3) (2) According to the present invention, this statistic can be tracked by, for example, calculating the mean of the difference over a number of occurrences, i.e., delta SSa/n (3) where n is the number of differences which are reported. After the mean value has been taken for a statistically significant number of delta statistic calculations, one would expect this value to approach PSVB-PSMB. A variance from this expected value can be detected by the system. Then, the system (and/or the operator) will lmow that there is a problem associated with the output transmit powe: of that transceiver. For example, the power setting stored in the MSC for that particular transceiver may be incorrect. If several of the transceivers CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -14- show a discrepancy, then the PSVBIPSMB setting may be stored incorrectly. This recognition will permit the system and/or the network operator to adjust output transmit powers in an appropriate direction. Of course those skilled in the art will appreciate that the actual calculation used to cornpare the signal strengths can vary and yet still provide the operator and/or system with the desired information for power monitoring. For example, an alternative is to calculate the delta statistic including the PSVB-PSMB information, e. g. , by calculating: Ssd = Sst(B3) - SsJB3) - (PSVB-PSMB;) (4) for the example provided above. Consider the exemplary delta statistics compiled as illustrated in Figure 4. Therein, the delta statistic has been accumulatec[ for five different devices, i.e., transceivers, associated with a particular cell or base station. The middle column represents the delta statistic as computed using equation (2) and the rightmost column (delta..) represents the delta statistic as computed using equation (4). These exemplary values represent the mean (or median) delta statistic taken over a period of time that is sufficient to make the delta information statistically reliable, e.g., more than about 400 reported values. For this example, PSVB-PSMB is equal to zero,- such that both columns of values are the same. If the delta statistic is greater than some predetermined threshold above or below zero, e.g., three in this example, then the device can be identified as having an incorrect output power. Such an identification can lead to an operator being notified, an automatic adjustnnent or both. For example, the operator could be notified that device number 4 is operating outside of the established, permissible range of deltas. Then, the operator can adjust the output power of device number 4 and/or the PSVB/PS:MB setting. Alternatively, this adjustment could be automated by providing fef:dback within the radiocommunication system as will be described below. Another example of an accumulated delta statistic is illustrated in Figure 5. For this example, unlike the example of Figure 4, PSVB-PSMB has been set equal CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -15- to -7, however those skilled in the art will recogiiize that this value can take any desired magnitude. Since PSVB-PSMB is not equal to zero in this example, the two different delta statistic computation techniques result in different values, but each show that device 4 is again problematic in terms of its monitored power. As mentioned above, exemplary embodinzents of the present invention provide that the delta statistic is computed based on a difference between measurements made on (1) a measurement channel (e.g., control channel) associated with a target cell and (2) a traffic channel associated with the same target cell after handoff. According to other exemplary embodiments of the present invention, the delta statistic can be computed by measuring the mobile station's current traffic channel (instead of the target cell's measurement channel) and setting delta as: Ssd = Sst(B3) - Ss~(B1) -HYST (S~ As with equation (2), equation (5) can also be modified to include a PSVB-PSMB factor, if so desired. As mentioned earlier, it may be desirable to provide automatic feedback within the radiocommunication system to implenient changes to the PSVB/PSMB settings, the individual transceiver output transmit power settings or both. Figure 6 is a block diagram illustrating how a paramete:r automation processor (PAP) 600 can interact with other nodes within the radiocornmun:ication system to provide automated power output control which is responsive to the delta statistical monitoring described above. Therein, PAP 600 periodically receives reports from MSC 610 regarding the delta statistic. These reports may take the fcirm of raw data, e.g., individual groups of measured deltas for each transceiver, or processed data, e.g., wherein the mean or median of each group has been calculated. In any event, PAP 600 may include a preprocessor function 620 which :receives the raw or processed data and formats the data or performs further calculations, e.g., takes the mean or CA 02356906 2001-06-26 WO 00/41337 PCT/SE99/02344 -16- median for each transceiver. Then, the preproc;essed information can be passed to a logic function 630 within PAP 600. The logic function 630 operates on the preprocessed delta statistics to determine whether the PSVB/PSMB and/or individual transceiver output transmit power settings stored in MSC 610 need to be updated or adjusted. Those skilled in the art will appreciate that the particular logic employed will depend upon the circumstances under which a network operator desires that a setting or output power be adjusted. Purely as an example, the following algorithm can be incorporated within logic function 630 to determine when an adjustment is needed to the PSVB setting in MSC 610. First, logic function 630 evaluates the pireprocessed delta data received from preprocessor 620 to identify a set of transceivers managed by MSC 610 having the characteristics that (1) at least 50% of the transceivers, (2) have a delta statistic that deviates less than or equal to 2 dB from the average delta (Ss,,õg) of the set. Finding such a set, logic function 630 changes the PSVB setting to be equal to the previous PSVB setting plus the average delta of the set, i.e., : PSVB = PSVB + Ss,õg This new PSVB value is then transmitted from :PAP 600 to MSC 610 where it is stored and applied to the various base stations E40 controlled by that MSC. The individual transceivers' output transmit power settings can also be controlled using a similar average delta statistic processing in logic function 630. Note that although PAP 600 is shown as a separate node relative to MSC 610, it can be incorporated therein if so desired. Moreover, the changes determined within PAP 600 can be automatically implemented within ttie radiocommunication system, e.g., by replacing the stored value in MSC 610 with the changed value determined by PAP 60Q. or the changes can be selectively ',implemented by an intervening network operator by displaying or otherwise outputting the results of logic function 630 thereto. CA 02356906 2001-06-26 WO 00%41337 PCT/SE99/02344 -17- Those skilled in the art will appreciate that the foregoing techniques can be used to improve handoff determinations in a variety of ways. The above- described exemplary embodiments are intended to be illustrative in all respects, rather than restrictive, of the present invention. Thus the present invention is capable of many variations in detailed implementation that can be derived from the description contained herein by a person skilled in the art. All such variations and modifications are considered to be within the scope and spirit of the present invention as defined by the following claims.