WO2001078423A1

WO2001078423A1 - Method and apparatus for originating gsm-900/gsm-1900/gsm-1800 cellular calls without requiring full power at call initiation

Info

Publication number: WO2001078423A1
Application number: PCT/US2000/009599
Authority: WO
Inventors: John R. Doner
Original assignee: Airnet Communications Corporation
Priority date: 2000-04-11
Filing date: 2000-04-11
Publication date: 2001-10-18
Also published as: AU2000242275A1

Abstract

A method and apparatus to provide call origination without requiring full power in a time division multiple access ('TDMA') cellular phone system (fig.2, fig.4). A time delay is measured (410) from the beginning of a timeslot containing a request (400) for a call setup to the beginning of the request (400). An estimated distance is derived from the time delay (420). The estimated distance is used to address a look-up table to arrive at a distance index (430). A power level index (440) is selected from the minimum of either the distance index (430) plus a fixed integer or a maximum value. The fixed integer is a value greater than zero and is based on the propagation characteristics of the particular cell. The maximum value is the power level that will sustain an acceptable signal quality at a cell site boundary. The power level index (440) is then used to address the look-up table to arrive at assigned power level (450).

Description

METHOD AND APPARATUS FOR ORIGINATING

GSM-900/GSM-1900/GSM-1800 CELLULAR CALLS

WITHOUT REQUIRING FULL POWER AT CALL INITIATION

FIELD OF THE INVENTION

This invention relates generally to time division multiple access ("TDMA") cellular phone systems such as GSM-900, GSM-1900, and GSM-1800. In particular, the present invention relates to forward link power control for call origination in a TDMA cellular phone system.

BACKGROUND OF RELATED ART

A conventional cellular phone system 100 is shown in Fig.

1. As illustrated in Fig. 1, the cellular phone system 100 includes a plurality of cells 110a, 110b, a mobile subscriber unit 120, a plurality of base transceiver stations (BTS) 105a,

105b, communication lines 140, a mobile telecommunications switching office (MTSO) 130, an interface 150 and a switched telephone network 160. The cellular phone system 100 has a fixed number of channel sets distributed among the BTS 105a, 105b serving a plurality of cells 110a, 110b arranged in a predetermined reusable pattern.

The mobile subscriber unit 120, in a cell 110a or 110b, communicates with the BTS 105a or 105b via radio frequency (RF) means, specifically employing one of the fixed number of channels. The BTS 105a, 105b communicate with the MTSO 130 via communication lines 140. The MTSO 130 communicates with the switched telephone network 160 via the interface 150.

In the cellular phone system 100, the cell areas typically range from 1 to 300 square miles. The larger cells typically cover rural areas, and the smaller cells typically cover urban areas. Cell antenna sites utilizing the same channel sets are spaced by a sufficient distance to assure that co-channel interference is held to an acceptably low level. The mobile subscriber unit 120 in a cell 110a has radio telephone transceiver equipment which- communicates with similar equipment in BTS 105a, 105b as the mobile subscriber unit 120 moves within a cell or from cell to cell .

Each BTS 105a, 105b relays telephone signals between mobile subscriber units 120 and a mobile telecommunications switching office (MTSO) 130 by way of the communication lines 140.

The communication lines 140 between a cell site, 110a or

110b, and the MTSO 130, are typically Tl lines. The Tl lines carry separate voice grade circuits for each radio channel employed at the cell site, and data circuits for switching and other control functions.

The MTSO 130 in Fig. 1 includes a switching network (not shown) for establishing call connections between the public switched telephone network 160 and mobile subscriber units 120 located in cell sites 110a, 110b and for switching call connections from one cell site to another. In addition, the MTSO 130 includes a dual access feeder (not shown) for use in switching a call connection from one cell site to another. Various handoff criteria are known in the art and utilize features such as phase ranging to indicate the distance of a mobile subscriber unit from a receiving cell site, triangulation, and received signal strength to indicate the potential desirability of a handoff. Also included in the MTSO 130 is a central processing unit (not shown) for processing data received from the cell sites and supervisory signals obtained from the switched telephone network 160 to control the operation of setting up and taking down call connections.

Typically in a given cell site many subscriber calls will be supported simultaneously through a single BTS. The transmission function of the BTS is supported by either by a single broadband multicarrier amplifier, which shares its total power among all subscribers, or by multiple broadband single carrier power amplifiers, each of which serves a single channel.

In the first generation analog cellular systems, the BTS would share its power equally among all the subscribers in the cell site. The BTS would provide constant transmit power to the mobile subscriber unit in the forward link (i.e., the base station to mobile transmit link) . The BTS would transmit the same amount of power if the mobile subscriber unit was close to the BTS or if the mobile subscriber unit was at the cell boundary. One of the reasons to implement this type of power control was the simplicity in the design of the BTS.

However, transmitting the same amount of power regardless of the position of the mobile subscriber unit generates significant co-channel interference, thereby reducing frequency reuse capability. Likewise for a multi-carrier amplifier, constant power transmission does not permit efficient use of the resources of the amplifier. The need for transmit power in cellular systems decreases proportional to the inverse of the distance R that the mobile unit is from the BTS, raised to the

1 fourth power, i.e. Power «— ..As a result, typically the average ^* power level needed per subscriber is only one-third of the maximum power required (i.e., the power level needed to assure adequate call quality at the cell boundary) in a given cell . Thus, by constantly transmitting at maximum power to all mobile units regardless of varying distance of the mobile units from the BTS, the first generation analog cellular systems had serious shortcomings. In their attempts to manage the relatively scarce bandwidth resource, wireless system operators were hampered by the co-channel interference-generating aspects of the first generation systems. This co-channel interference hampered system operators ' efforts to maximize the efficient use of scarce bandwidth by reusing frequencies wherever possible. Furthermore, the first generation analog cellular systems did not efficiently use RF power amplifiers. This shortcoming was particularly acute where a multi-carrier power amplifier was present. In many installations, multi-carrier power amplifiers were significantly oversized, in order to provide a fixed transmission power level to all mobile subscriber units, even those that could be served at much lower power levels.

In some second generation time division multiple access ("TDMA") digital cellular systems, a forward link control mechanism has been implemented to reduce co-channel interference. In addition, forward link control provides additional benefits of improved efficiency in systems employing multi-carrier power amplifiers. Current multi-carrier broadband amplifier technology places a premium on transmit power conservation, because the cost per watt for broadband multi -carrier amplifiers is quite high. In fact, for some cellular systems, power levels of 100 watts require combining or ganging together separate modules. Conserving power in the broadband multi-carrier amplifier is therefore in the interests of designers of Global System for Mobile ("GSM") based cellular phone systems, such as GSM-900, GSM-1900, (formerly PCS1900) and GSM-1800 (formerly DCS-1800) , as well as TDMA systems, such as IS-136.

The forward link power control minimizes transmit power in the forward link direction by transmitting signals at the lowest possible level that maintains an acceptable signal quality. The forward link power control also serves to minimize co-channel interference and to conserve power in both the mobile subscriber unit and the base transceiver stations. The mobile subscriber unit continually measures the forward signal strength or signal quality (based on a bit-error rate) , and passes the information to the BTS or to the base station controller, which ultimately decides if and when the power level should be changed. Power levels may be stepped up or down in steps of 2 dBm from the peak power for the mobile subscriber unit to a minimum of 30 dB below peak power in a GSM cellular phone system for example.

The forward link power control capability is an essential tool for managing the resources for broadband base stations. The forward link power control allows a BTS to manage the subscribers collectively in order not to exceed the capacity of the multi- carrier amplifiers of the BTS.

However, forward link power control cannot be applied to a newly originating call until the call is already established, due to latency in the process of determining forward link signal and call quality at the mobile subscriber unit. This limitation requires that all new calls be started at full power, since there is no data initially available as to their distance from the base station. The power level can thereafter be adjusted downward, if possible, in the first few seconds of the call.

As a result of the initiation of origination calls with full power, transmit power conservation may still remain a problem for the designer. Although the maximum power level for the new call may only be required for a few seconds, in a busy system, several new calls may originate within that same interval, requiring full power for several calls. The overall demand for power from the broadband amplifier is driven substantially higher by this call setup paradigm.

There is thus a need for a method and apparatus for originating cellular calls which does not require full power at call initiation.

SUMMARY OF THE INVENTION

In accordance with the principles of the present invention, a method for originating cellular calls that does not require full power at call origination is disclosed. A broadband transceiver system (BTS) estimates the distance of the mobile. subscriber unit from the BTS by measuring the time delay from the beginning of a control channel slot to the start of the notification message. In fact, all GSM systems perform this measurement in order to adjust the timing of the mobile subscriber unit transmission burst, to align the burst in the time slot of the TDMA RF signal. The BTS derives an estimated distance to the mobile subscriber unit from the measured time delay. The estimated distance is used to determine an index. The power level is then assigned by selecting the lower of either the index plus a fixed integer or a known maximum value. Another embodiment of the present invention in accordance with the principles of the present invention is an apparatus for originating a cellular call that does not require full power. A controller in a BTS measures the time delay from the beginning of a control channel timeslot to the start of a notification message from a mobile subscriber unit. An estimated distance is derived from the measured time delay. The estimated distance is used to determine an index. The power level is then assigned by selecting the lower of either the index plus a fixed integer or a known maximum value .

BRIEF DESCRIPTION OF THE DRAWINGS Features and advantages of the present invention will become apparent to those skilled in the art from the following description with reference to the drawings, in which:

Fig. 1 illustrates a conventional cellular phone system.

Fig. 2 illustrates a TDMA cellular phone system which includes a call origination which does not require full power in accordance with the principles of the present invention.

Fig. 3 is a block diagram of a BTS in the TDMA cellular phone system of Fig. 2.

Fig. 4 is a flow diagram of the call origination which does not require full power in accordance with the principles of the present invention.

Fig. 5 is an illustration of a look-up table used in Fig. 4.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS The present invention provides for improved power management for a multi-carrier amplifier in a broadband transceiver system (BTS) .

In particular, the present invention provides for estimating the distance from a BTS to a mobile subscriber unit based on a measured time delay. The time delay is measured from the leading edge of a timeslot in a control channel dedicated for uplink communications (from the mobile subscriber unit to BTS) . Alternatively, in the case of a GSM system, the time delay is measured from the timing advance measurement performed from the random access control channel burst during call initiation.

The time delay is then used to estimate the distance of the mobile subscriber unit from the base station by dividing the time delay by the speed of light.

The estimated distance is then used to compute an index. The index is used to assign a power level to the originating call by selecting the minimum between the index plus a fixed integer and a maximum value .

Fig. 2 shows a block diagram of a TDMA cellular phone system 200 that includes originating cellular calls which does not require full power in accordance to the principles of the present invention.

The TDMA cellular phone system 200 includes three groups: a mobile subscriber unit 210, a base station subsystem ("BSS")

220, and a network subsystem 240. The mobile subscriber unit 210 may referred to as a

"handset," a "mobile unit," a "portable terminal" or "mobile equipment". The mobile subscriber unit 210 provides an interface for the subscriber to communicate with the TDMA cellular phone system 200. The BSS 220 includes a base transceiver station ("BTS"), 225a or 225b and a base station controller ("BSC") 230.

The functions of BTS 225a or 225b are to connect the mobile subscriber unit 210 to the TDMA cellular phone system 200. The BTS 225a or 225b tasks further include channel coding/decoding and encryption/decryption. BTS 225a or 225b comprises radio transmitters and receivers, antennas, and other equipment required for RF communication with mobile units.

The BTS 225a or 225b provides radio coverage for a specific geographical area called a cell. Multiple BTS are connected to and controlled by the BSC 230.

The BSS 220 provides for management of radio resources within either the BTS 225a, 225b or the BSC 230. The mobile subscriber unit 210 normally sends a report of its received signal strength to the BSS 220 every 480 ms . With this information the BSS 220 manages such decisions as when to initiate handovers to other cells, change the BTS, 225a or 225b, adjust transmitter power, etc. These functions can be performed in various manner as will be apparent to those skilled in the relevant art. For example, GSM specifies radio resource management as a BSC function, but GSM architecture permits many radio resource management tasks, such as initiation of handover, to be performed in the BTS . The network subsystem 240 includes a mobile switching center

("MSC") 245, a home location register ("HLR") 250, a visitor location register ("VLR") 255, authentication center ("AuC") 260, an equipment identity register ("EIR") 265, and an operation and maintenance center ("OMC") 270. The MSC 245 provides for registration, authentication, location updating, handovers, and call routing to a roaming subscriber. With respect to the mobile subscriber unit 210, the

MSC 245 acts like a standard exchange in a fixed network and additionally provides all the functionality needed to handle a mobile subscriber. The MSC 245 may also have a gateway function for communicating with other networks.

The HLR 250 maintains a database used for management of mobile subscribers. For each mobile unit 210 the HLR 250 stores the IMSI, mobile subscriber unit 210 ISDN number and current visitor location register ("VLR") address. Generally, the information stored in the HLR 250 concerns the location of each mobile subscriber unit 210, information that is necessary to be able to route calls to each mobile subscriber unit 210 managed by the HLR 250. The HLR 250 also maintains the services associated with each mobile subscriber unit 210. One HLR may serve several MSCs .

The VLR 255 informs the MSC 245 of the current location of the mobile subscriber unit 210. • The VLR 255 also provides selected administrative information from the HLR 250, necessary for call control and provision of the subscribed services, for each mobile subscriber unit 210 that is located in a cell controlled by the VLR 255. The VLR 255 is connected to one MSC 245 and is normally integrated into the MSC 245 hardware. The AuC 260 maintains a protected database that holds a copy of the secret electronic "key" that is stored in each subscriber's SIM card. The key is used for authentication and encryption over the radio channels. In this manner, the AuC 260 provides additional security against fraud. It is normally located close to each HLR 255 within the TDMA cellular phone system 200.

The EIR 265 maintains a database of all valid mobile subscriber unit 210 equipment within the TDMA cellular phone system 200. Each mobile subscriber unit 210 is identified by its

IMEI . The EIR 265 includes three subsidiary databases: (1) a

"white list" for all known, good IMEIs; (2) a "black list" for bad or stolen handsets; and (3) a "grey list" for handsets/lMEIs whose status is uncertain. The OMC 270 directs the management system that oversees the functions of the TDMA cellular phone system 200. The OMC 270 assists a network operator in maintaining satisfactory operation of the TDMA cellular phone system 200. Hardware redundancy and intelligent error detection mechanisms contained in OMC 270 help prevent network down time. The OMC 270 is responsible for controlling and maintaining the MSC 245, the BSC 230, and BTS

225a, 225b. The OMC 270 may also be in charge of an entire public land mobile network or just some parts of the public land mobile network. The TDMA cellular phone system 200 may operate with several different but related network protocols, including the three variants of the Global System for Mobile Communication (GSM) : GSM-900, GSM-1900, or GSM-1800. Although the present invention is embodied with the GSM-900, GSM-1900, or GSM-1800 network protocols, the present invention is applicable to other TDMA network protocol systems .

In the current embodiment, the present invention is part of a digital multi-carrier broadband wireless transceiver system (BTS) of the TDMA cellular phone system 200. Fig. 3 illustrates a block diagram of the BTS of the TDMA cellular phone system 200 which includes the present invention of call origination without requiring full power.

As shown in Fig. 3, the modern digital ulti-carrier broadband wireless transceiver system (BTS) 300 includes a network interface module 310, a digital signal processing (DSP) module 320, a combiner module 330, channelizer modules 340a, 340b, a broadband RF transceiver 350, a multi-carrier power- amplifier (MCPA) 360, a central processing unit 370, and a memory 380. Alternatively, the BTS 300 may employ multiple single carrier power amplifiers (SCPA) in lieu of a single MCPA 360.

The network interface module 310 provides a connection between the BTS 300 and a MTSO. In this particular example, the network interface module 310 provides ninety-two (92) 16 kbps subrate voice channels.

The network interface module 310 is also interfaced with the DSP module 320. The DSP module 320 provides for channel coding and modulation of thirteen (13) kbps voice channel data from the network interface module 310. The DSP module 320 multiplexes eight (8) channels into a single baseband signal for upconversion to an intermediate frequency (IF) and for combining with other RF carriers by the combiner module 330. The DSP module 320 also provides the equalization, demodulation and channel decoding from received channels of RF carriers that have been downconverted to a baseband signal by the channelizer modules 340a, 340b.

The combiner module 330 receives the 'baseband RF carriers from the DSP module 320. Each RF carrier is filtered and upconverted to a unique intermediate frequency (IF) . All of the

RF carriers in a five (5) MegaHertz (MHz) bandwidth are simultaneously combined into a single composite IF signal. This digital IF signal is then transferred to the broadband RF transceiver 350.

The channelizer modules 340a, 340b receive a digital composite IF signal from the broadband RF transceiver 350. The digital composite IF signal consists of all twenty-five (25) of the 200-kiloHertz (kHz) RF carriers in a 5 MHz bandwidth. The channelizer modules 340a, 340b filter and downconvert each RF carrier to a baseband signal for processing by the DSP module 320.

The broadband RF transceiver 350 converts the digital signals for transmission to mobile subscriber units. The broadband RF transceiver 350 also converts received analog signals to digital signals for processing by the BTS 200.

The MCPA 360 is typically an ultra-linear, multi-carrier, high power amplifier. The MCPA 360 receives a composite broadband signal from the broadband RF transceiver 350 and provides as much as 48dB of gain. The power output of individual RF carriers are determined by downlink power control algorithms entirely within the broadband RF transceiver 350.

The CPU 370 hosts all of the BTS 300 low level control, call processing, and operation and maintenance application software which includes the software embodiment of the present invention of cellular call origination without requiring full power.

The memory 380 includes non-volatile memory storage of the real-time operating system and application software. The application software that is stored in memory 380 includes the present invention of call origination without requiring full power.

As disclosed, the BTS 300 includes the present invention which is based on determining the distance of the mobile subscriber unit from the BTS 300. The primary variable dictating the transmit power requirement for call origination is the distance between a BTS and a mobile subscriber unit. A new call may be assigned the correct power at call origination provided that an approximation of the distance was available.

TDMA protocols such as the GSM-based protocols in fact support such an estimation, because of certain synchronization mechanisms required for the TDMA aspect of the GSM-based protocols .

Specifically, a single RF (radio frequency) carrier in GSM supports eight simultaneous calls, each broadcasting for a short burst of time in a repeating cycle. The individual transmit time of a single caller is called a time slot, and eight consecutive time slots are called a frame. The frames represent contiguous periodic repetitions of the eight time slots, and to avoid interference between mobiles sharing an RF carrier, each mobile on a specific carrier transmits only during its assigned time slot .

Implicit in the TDMA scheme is the need for synchronization: the distinct mobiles sharing an RF carrier must be operating with a common clock in order collectively to honor the time slot boundaries. This common clock is derived from the common forward link data stream that they share, which is likewise divided into frames and time slots. Thus each mobile tracks the beginnings of frames, and can offset its own uplink transmission by the amount necessary to synchronize with the tracked frames. However, tracking the downlink clock is not adequate for full synchronization, because mobile subscriber units are at different distances from the BTSs. A mobile subscriber unit farther from the BTS receives the downlink timing data later than a mobile close to the BTS, and its uplink signal back to the base station likewise takes longer to arrive. Using only the downlink timing data, mobile subscriber units would operate with the risk of interference resulting from overlapping time slot data bursts on uplink transmissions, especially in circumstances where a more distant mobile occupies an adjacent time slot preceding the time slot of a closer mobile.

GSM provides a mechanism called the timing advance to prevent this. In effect, on the first contact with the BTS

(during call establishment) , each mobile transmits a short data burst in the Random Access Channel ("RACH"), and does so using its local estimate of the base station clock as received on the downlink control channel. The distance of the mobile unit from the BTS can then be approximated by the base station by measuring the time delay of the mobile burst from the leading edge of the RACH time slot.

This distance estimate can support a means to assign an initial power level for the forward link supporting the new call. Other factors can be considered to determine the reliability of this metric. First, the linearity of the distance between the mobile unit and the BTS is not perfect : The mobile may be shadowed by an obstruction, such that there may be a delayed reflected signal or multipath component which is stronger than the direct signal component that is attenuated by the obstruction. However, this effect serves only to increase the distance estimate, since the reflected signal path is necessarily longer than the direct signal path. Therefore, the initial

^■forward link power assigned will err on the conservative side. Second, any situation in which the mobile signal may be attenuated by obstructions or fading would seem to dictate that an initial signal level assigned based on distance might be inadequate. This should never be the case in practice, because the RF link budget specified for a cell normally provides for all sources of signal fading at the distance of the cell boundary. Therefore, modifying that 'component of signal power based on distance alone does not affect the fading margins already built into the link budget, and call setup at lesser power levels (based on distance) should be as successful as call setups at the maximum distance and power level for the cell.

Fig. 4 illustrates a flow diagram of call origination without requiring full power in accordance with the principles of the present invention in the TDMA cellular phone system 200.

In step 400, the BTS 300 receives a signal to initiate a call from the mobile subscriber unit 210. The mobile subscriber unit will notify the BTS 300 over the RACH channel. The RACH channel is a control channel that is specifically reserved for mobile subscriber units to notify a BTS about initiating call processing. The RACH channel is divided into timeslots where the mobile subscriber units will notify the BTS by a notification message within a single timeslot. In step 410, the BTS 300 measures the time delay, t_dl, between the beginning of the RACH timeslot and the actual request for call origination signal by the mobile subscriber unit.

In step 420, the measured time delay, t_dl, is converted to an estimated distance, D_est, by dividing the time delay, t_d, by the speed of light, c, illustrated by equation (1) :

D_est = t_d/c (1)

In step 430, the D_est is used to determine a distance index,

J from a look-up table which is illustrated in Fig. 5. Although the current embodiment of the present invention includes a lookup table, the present invention may use algorithms or other types of software techniques to derive the necessary information.

The look-up table is initially determined during the setup of the cell site. For each N power level of a given cell site, P_N, a corresponding maximum distance, D., is determined for each power level . The choice of D_x should ideally be based on the initial design measurements made in support of the cell site.

A corresponding index is also determined for the look-up table.

From the estimated distance, D_eεt, distance index J is retrieved from the look-up table based on the following equation

(2) that is summarized by:

J = minimum{i|D_est ≤D_^ for i ε (l,...,N)} (2)

In other words, the index J is the minimum value of i for which D_est is less than or equal to D where i represents a specific one of N power levels in a given cell.

In the event that D_est > D_N, the distance index, J, is chosen to be the highest value, N.

In step 440, a power level index L is determined by selecting the lower of either J^" plus a fixed integer K, or N. The fixed integer, K, is chosen to be greater than zero. The fixed integer, K, provides for an error margin on the conservative side, allowing assignment of a power level higher than that dictated solely by the estimated distance from the mobile subscriber unit. K is preferably cellsite specific, based on the known propagation characteristics of the cell site, and other knowledge concerning terrain, obstructions, etc.

The power level index L is then used to address the look-up table of Fig. 5 to determine the appropriate power level. The power level is then assigned by the BTS 300 to the call initiated by the mobile subscriber unit.

While the invention has been described with reference to the exemplary embodiments thereof, those skilled in the art will be able to make various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention.

Claims

CLAIMSWhat is claimed is:

1. A method for originating a cellular call, said method comprising:

detecting a request for a call setup on a control channel; measuring a time delay within a timeslot of said request; and allocating a power level to said call setup based on said time delay.

2. The method for originating a cellular call of claim 1, wherein:

said time delay is measured from a start of said timesiot to a start of said request within said timeslot.

3. The method for originating a cellular call of claim 1, further comprising:

converting said measured time delay to an estimated distance.

4. The method for originating a cellular call of claim 3, wherein: said converting to said estimated distance is derived from dividing said time delay by the speed of light.

5. The method for originating a cellular call of claim 3, further comprising:

deriving an index from said estimated distance.

6. The method for originating a cellular call of claim 5, wherein:

said deriving includes using said estimated distance to address a look-up table to derive said index.

7. The method for originating a cellular call of claim 5, wherein:

said allocating of said power level is based on selecting the minimum value of one of said index plus a fixed integer and a maximum value.

8. The method for originating a cellular call of claim 7, wherein:

said fixed integer is a value greater than zero based on propagation characteristics.

9. The method for originating a cellular call of claim 7, wherein:

said maximum value is the minimum value of power that will sustain an acceptable signal quality at a cell site boundary.

10. The method for originating a cellular call of claim 7, wherein:

said minimum value is used to address a look-up table to derive said power level .

11. An apparatus for originating a cellular call, said apparatus comprising:

a power source; a broadband RF transceiver; and a controller wherein said controller allocates a power level from said power source for a call being processed by said broadband RF transceiver based on a time delay within a call set-up request on a control channel .

12. The apparatus for originating a cellular call of claim 11, wherein:

said controller measures said time delay from a start of the timeslot which contains said request to a beginning of said request .

13. The apparatus for originating a cellular call of claim 11, wherein:

said controller derives an estimated distance from said time delay.

14. The apparatus for originating a cellular call of claim 13, wherein:

said estimated distance is derived from dividing said time delay by the speed of light.

15. The apparatus for originating a cellular call of claim 13, wherein:

said controller addresses a look-up table with said estimated distance to arrive at an index.

16. The apparatus for originating a cellular call of claim 15, wherein:

said controller allocates said power level based on the minimum of one of said index plus a fixed integer and a maximum value.

17. The apparatus for originating a cellular call of claim 16, wherein:

18. The apparatus for originating a cellular call of claim 16, wherein:

said maximum value is a value of power that will sustain an acceptable signal quality at a cell site boundary.

19. The apparatus for originating a cellular call of claim 16, wherein:

said controller uses said minimum value to address a lookup table to arrive at said power level .

20. The apparatus for originating a cellular call of claim 11, wherein:

said controller estimates said time delay from timing advance functionality in a time division multiple access system.

21. The apparatus for originating a cellular call of claim 20, wherein:

said time division multiple access system is a GSM-based system.

22. The apparatus for originating a cellular call of claim 20, wherein: said time division multiple access system is an IS-136 TDMA system.

23. The apparatus for originating a cellular call of claim 21, wherein:

said time division multiple access system is one of a GSM-1900 system, a GSM-1800 system, and a GSM-900 system.