WO2001048942A1

WO2001048942A1 - Reporting system for wireless repeater for indicating uplink mobile receive level

Info

Publication number: WO2001048942A1
Application number: PCT/US2000/035249
Authority: WO
Inventors: Thomas Schmutz; Terry L. Williams; John R. Noll
Original assignee: Airnet Communications Corporation
Priority date: 1999-12-29
Filing date: 2000-12-22
Publication date: 2001-07-05
Also published as: AU2597701A

Abstract

A method and apparatus for automatically controlling power level in a backhaul channel of a wireless repeater communication system. The backhaul communication channel is used to efficiently manage one or more mobile transceiver stations in a wireless cellular telecommunications system having a base transceiver station (27) located in a home cell that serves a plurality of adjoining cells each having a repeater (28) located therein. Communication signals between the repeaters (28) and the home base transceiver station (27) occurs over channels on the backhaul communication link. The repeaters (28) receive signals from the mobile stations. An indication of the measured power level is then sent by the repeater (28) to the serving home base transceive (27) station via an uplink hannel on the backhaul communication link. This power level represents the actual power level of the signal at the mobile transceiver station. Using this indication of the actual signal power level, the base transceiver station (27) can more efficiently manage the mobile transceiver stations and the frequencies assigned to the system.

Description

REPORTING SYSTEM FOR WIRELESS REPEATER FOR INDICATING UPLINK MOBILE RECEIVE LEVEL

BACKGROUND OF THE INVENTION

Field of the Invention

The instant invention pertains generally to the field of managing

transceiver units in a wireless cellular communication system. More

particularly, the invention describes a method and apparatus for

automatically controlling power levels in a wireless cellular system having

repeaters.

Description of Related Art

In wireless cellular communication systems having repeaters, the

signal from the mobile transceiver stations are first received by the

repeater. These repeaters typically have automatic level control (ALC)

circuitry that may attenuate or boost the received signal power level to

ensure that the signal transmitted by the repeater is received by the

serving home base station at a sufficient power level. The ALC alters the

characteristics of the received signal including important information such

as the received power level. Furthermore, repeaters may additionally

translate the frequency of the signal received from the mobile transceiver

station to another frequency before sending the signal to the serving home base station. As a result, frequency translation further alters the

characteristics of the original signal.

One of the consequences of automatic level control and frequency

translation is that the power level of the signal that is transmitted from

the mobile transceiver station to the repeater station is not necessarily

correlated to the signal level that is transmitted from the repeater station

to the serving home base station. This is because the home base station

only receives signal power level information from signals modified by the

repeater's ALC. As a result, any indication of the signal power level that

the home base station sends to the managing base station controller will

not necessarily be an accurate representation of the actual signal power

level of the mobile transceiver station or pilot signal from an unused

channel.

In wireless cellular communication systems having repeaters, it is

desirable for the base transceiver station (BTS) to have an accurate

indication of the actual received power levels on all channels in the

system at all times received by the respective repeaters. Such

information permits the BTS to effectively manage the mobile transceiver

units and repeater stations and perform actions such as handoffs. In a

repeater based wireless cellular communications system, any power level

measurement made by the BTS for the channels provided by the repeaters

are at best mere approximations. This method requires the BTS to rely

upon power level measurements of signals received from the repeater

stations for the purpose of managing channel allocation within the system. This solution is less than satisfactory because the power level of

the signals received from the repeater station which are retransmitted to

the BTS are not correlated to the actual strength of the signal that the

repeater station receives from the mobile transceiver stations.

Accordingly, there is a need to provide a more effective solution to the

problem of controlling a wireless cellular communication system having

one or more repeaters.

SUMMARY OF THE INVENTION

The invention discloses a method and apparatus for more

efficient control of a cellular communication system that uses repeaters.

The invention provides a method for managing one or more mobile

transceiver units in a wireless cellular communication system. The

wireless cellular communication system can include a base transceiver

station (BTS) that is located within a home cell having one or more

neighboring cells that are located substantially adjacent to the home cell.

One or more of the adjacent cells can have a repeater station located

within its boundary. The repeaters receive signals from the mobile

transceiver units via an uplink communication channel. The repeater

measures the signal power level of the received signal. Subsequently, the

repeater transmits a backhaul signal to the BTS on a backhaul

communication link. The backhaul signal includes at least an indication of

the power level as measured by the repeater station. According to one aspect of the invention, the backhaul

communication link can have one or more traffic channels and one or

more control channels. An indication of the power level may be

transmitted on a traffic and/or control channel. The control channel can

be a dedicated control channel (DCCH), such as standalone dedicated

control channel (SDCCH) or a random access control channel (RACH) .

According to another aspect of the invention, the backhaul

communication link can include one or more time division multiplexed

(TDM) channels. In that case, an indication of the power level may be

transmitted over one or more of the TDM channels.

According to another embodiment of the invention, the indication

of received power level at the repeater can be digitally encoded within the

backhaul signal. This can be achieved by generating power level data that

is a digital representation of the power level of the signal that is measured

at the repeater. After demodulating the received signal, the power level

data along with the demodulated signal can be formatted for

transmission. The formatted power level data along with the information

contained in the demodulated signal can then be modulated and

transmitted over the backhaul communication link. The power level data

can be transmitted within a control channel, such as a stand alone

dedicated control channel or within a traffic channel (TCH).

According to an alternative embodiment, the method for managing

one or more mobile transceiver units may further include selectively

controlling a backhaul signal transmitted power level to indicate the signal power level received from the mobile transceiver units. This process

includes generating power level data that is a digital representation of the

power level that is measured at the repeater. This power level data is

then correlated to a predetermined transmitter power level that is

associated with the measured received power level. Based on this

information, the transmitter of the repeater is controlled so as to transmit

over the backhaul link at a predetermined power level.

According to an alternative embodiment, the invention includes a

wireless cellular communication system having a BTS located within a

home cell. The system contains one or more neighboring cells that are

located substantially adjacent to the home cell. Each of the adjacent cells

contains a repeater station located therein. The repeater stations each

contain a receiver to receive signals from mobile transceiver stations via

an uplink communication channel. Suitable circuitry and any necessary

software in the repeater stations measure the signal power level of the

received signal. The repeater also contains a transmitter that has the

capability to send a signal from the repeater to the home BTS via a

backhaul communication link. Suitable control circuitry and any

necessary software is provided to control the transmitter to send an

indication of the measured signal power level as well as the actual traffic

portion of the signal to the BTS via the backhaul communication link.

The backhaul link in the wireless system has one or more traffic

channel for sending a portion of the received signal. Additionally, the

backhaul link has one or more control channels that can be used for sending an indication of the power level that is measured by the repeater

station. For example, the control channel on the backhaul link may be a

random access channel (RACH) or a dedicated control channel such as

the standalone dedicated control channel (SDCCH). According to another

aspect of the invention, the backhaul communication link may be a time

division multiplexed (TDM) channel, and the power level indication can be

transmitted on one of the TDM channels.

According to another aspect of the invention, the repeater can also

include circuitry and necessary software to digitally encode a

representation of the power level as measured at the repeater. In this

regard, the repeater can advantageously include a demodulator for

demodulating the received signal. The encoded signal power level and the

demodulated traffic portion of the signal can then be formatted for

transmission. Transmitter circuitry is provided for transmitting the

formatted signal power level over the backhaul link. The encoded

indication of the power level can be^' transmitted within a control channel

or a traffic channel.

In yet another embodiment of the invention, the wireless cellular

communication system includes a BTS located within a home cell having

one or more substantially adjacent cells, one or more of which may have

a repeater station located therein. In this embodiment, the system

provides a method for automatically controlling power levels in a backhaul

communication link having one or more channels. The method for automatically controlling power levels in the

backhaul communication link includes receiving at a repeater station,

communication signals from mobile transceiver units on an uplink channel.

A signal power level of the received signal is measured at the repeater

station. An indication of the measured signal power level is transmitted

by the repeater on the backhaul communication link. The BTS then

receives the indication of the signal power level signal that was

transmitted by the repeater. The BTS, under control of the base station

controller (BSC), can use this indication of the signal power level to

efficiently assign channels in the system. The signals received by the

repeater stations can be from mobile transceiver stations or from pilot or

test signals that are used to check unused channels.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown in the drawings embodiments which are presently

preferred, it being understood, however, that the invention is not limited

to the precise arrangements and instrumentalities shown, wherein:

FIG. 1 is a block diagram of a wireless communications system

employing wireless repeater stations.

FIG 2 is an exemplary arrangement of the wireless communications

system of FIG. 1 showing how wireless links are deployed through the

wireless repeater stations.

FIG. 3a illustrates an uplink GSM-type TDM frame.

FIG. 3b illustrates a downlink GSM-type TDM frame.

FIG. 4 is a block diagram of an exemplary single-omni directional

type translating repeater station of the type shown in the wireless

communication system of figure 1 .

FIG. 5 is a block diagram of an exemplary base transceiver station

of the type shown in the wireless communication system of Fig. 1 .

FIG. 6 is a flowchart showing an overview of a method for the

automatic management of mobile transceiver units and allocation of

channels in. a wireless communication repeater system.

FIG. 7 is a flowchart showing one embodiment of how power is

automatically controlled on a backhaul communication link in a wireless

communication system having repeaters. FIG. 8 is a flowchart showing an alternative embodiment of how

power is automatically controlled on a backhaul communication link in a

wireless communication system having repeaters.

FIG. 9 shows an exemplary lookup table that maps a corresponding

measured input power level to a predetermined output transmit power

level for the backhaul communication link.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram of a conventional wireless

communications system such as a Personal Communication System

("PCS") or other similar system. In this system, single-omni directional

type wireless translators/repeaters are deployed in peripheral cells of a cell

cluster to concentrate radio signal traffic to and from a broadband base

transceiver station ("BTS"). Those skilled in the art will readily appreciate

that sectorized wireless translators can also be used for this purpose.

However, for convenience, the system will first be described relative to a

single-omni directional type translator/repeater system.

The system 1 0 can include translator omni-directional antennas

1 1 -1 , 1 1 -2, . . . 1 1 -i, . . . 1 1 -n-2, 1 1 -n-1 and 1 1 -n (collectively omni¬

directional antennas 1 1 ), translating repeaters 1 2-1 , 1 2-2, . . . 1 2-i, . . .

1 2-n-2, 1 2-n-1 and 1 2-n (collectively repeaters 1 2), translator directional

antennas 1 3-1 , 1 3-2, . . . 1 3-i, . . . 1 3-n-2, 1 3-n-1 and 1 3-n (collectively

repeater directional antennas 1 3), BTS directional antennas 14-1 , . . .14-m (collectively BTS antennas 14), and broadband base

transceiver stations 1 5-1 , . . . 1 5-m (collectively BTSs 1 5) . System 1 0

can further include mobile switching center (MSC) 1 6, one or more base

station controllers 1 7 and a plurality of mobile transceivers 1 8-1 and 1 8-2

(collectively mobile transceivers 1 8).

Repeaters 1 2 conventionally receive radio signals from mobile

transceivers 1 8 through omni-directional antennas 1 1 and forward them

to BTSs 1 5 through translator directional antennas 1 3. Likewise, radio

signals transmitted from BTSs 1 5 through BTS antennas 14 are forwarded

by repeaters 1 2 to mobile transceivers 1 8. BTS 1 5 is responsible for

demodulating signals received from translators 1 2 through BTS antennas

14 and connecting these signals to the Public Switched Telephone

Network (PSTN) through MSC 1 6. In addition, BTS 1 5 modulates signals

received from the PSTN through MSC 1 6 to format them for transmission

through BTS antennas 1 4 to repeaters 1 2.

FIG. 2 illustrates the basic operation of repeaters 1 2. In particular,

repeaters 1 2 transmit signals to and receive signals from BTS 1 5 through

backhaul channel 1 9. Similarly, repeaters 1 2 transmit signals to and

receives signals from mobile transceivers 1 8 through ground link channel

20. Each of the ground link channel 20 and the backhaul channel 1 9 is

defined by an uplink carrier frequency and a downlink carrier frequency.

Because BTS 1 5 is stationary, repeaters 1 2 preferably employ directional

antenna 1 3 to transmit and receive signals over backhaul channel 1 9. In

contrast, because mobile transceivers 1 8 are not stationary and the repeater 1 2 is not sectorized, repeaters 12 preferably employ one or more

omni-directional antennas 1 1 A and 1 1 B respectively to transmit and

receive signals over ground link channel 20.

Communications between mobile transceivers 18, repeaters 12,

and BTS 1 5 can be performed using a variety of multiplexing schemes

that are well known in the art. For example, a time division multiplex

(TDM) scheme may be used for this purpose. FIG 3a shows a typical

uplink GSM TDM frame 21 comprising eight time slots, used for

transmission from a mobile user to a base station. The depicted GSM

TDM frame has a duration of 4.62 milliseconds, including eight time slots

of 0.58 milliseconds each. A sequence of digital bits makes up each time

slot. Portions of a time slot, or sub-time slots, are generally assigned

specific functions and are referred to herein as sub-channels. Time slots

can be configured to support user traffic or can be used for system

control information. Generally, for GSM-type TDM implementations using

a single RF carrier, one time slot is dedicated to transmitting control

information, while the remaining slots are available to transmit traffic

information. Traffic channels can carry conversations or data, as well as

information about the time slot itself.

In frame 21 of FIG. 3a Slot 0 contains control information and slots

1 -7 contain traffic data. Typical formats for the control and traffic sub¬

channels are shown in time slot details 22, 23. Detail 22 of time slot 4

shows typical GSM format traffic sub-channels including tail bits 22-1 ,

22-7 used to indicate the beginning and end of a time slot, data bits 22-2, 22-6 which contain the digitized call information, and training

sequence bits 22-4 used for equalization of multi-path signals. Stealing

bits 22-3, 22-5 are provided to indicate if suppression of time slot data

and replacement with priority data is requested. Finally, guard bits 22-8

are provided to keep the time frames separate. The number of bits

contained in a typical traffic sub-channel is shown below the sub-channel

designation in detail 22.

As noted earlier, in single TDMA RF carrier implementations, one

slot will generally be a dedicated digital control channel. As shown in

detail 23 of time slot 0, sub-channels in the uplink control time slot

generally include a stand-alone dedicated control sub-channel (SDCCH)

23-1 and a random access sub-channel (RACH) 23-2. The SDCCH sub¬

channel 23- 1 is used to transport information between the BTS 1 5 and a

specific mobile transceiver 1 8 to complete call set up or for transmission

of messages for a mobile transceiver 1 8 in idle mode. The RACH sub¬

channel 23-2 is used by the mobile transceiver 1 8 to request access to

the network during initial call set up.

FIG. 3b shows a typical GSM-type eight slot TDM frame 24 used in

downlink, base-to-mobile communications. Generally, the information

format in the traffic time slots 1 -7 remains the same, but more sub¬

channel data is included in the control time slot 0 as shown in detail 26.

Specifically, a frequency correction sub-channel (FCCH) 26-1 ,

synchronization sub-channel (SCH) 26-2, broadcast control sub-channel

(BCCH) 26-3, paging and access grant sub-channel (PAGCH) 26-4, are added to the SDCCH sub-channel 26-5 in the downlink control time slot.

However, the RACH sub-channel 23-2 is not included in the downlink

signal. The FCCH sub-channel 26-1 transmits frequency correction

information for a mobile transceiver 1 8 to correct its time base, while the

SCH 26-2 sub-channel transmits synchronization information for the

mobile to synchronize to the framing structure of the network. The BCCH

26-3 sub-channel transmits information to idle mobile transceiver 1 8

such as local area identification and neighbor cell information. Finally, the

PAGCH 26-4 sub-channel is used to page a mobile transceiver 18 and

grant access to a mobile transceiver 1 8 during call set up.

FIG . 4 is a detailed block diagram block of a repeater 1 2 that can

be used in connection with the present invention. The repeaters 1 2 can

comprise a ground sector transceiver 27 and backhaul transceiver 28. It

will readily be appreciated by those skilled in the art that other types of

transceiver architectures may be used to practice the invention and the

particular transceiver architecture as described herein is not intended be a

limitation on the invention.

In a preferred embodiment, transceivers 27 and 28 are each

capable of transmitting and receiving over a broad range of carrier

frequencies allocated to a service provider for multi-carrier operation.

However, the invention is not limited in this regard and more

narrowbanded transceivers can also be used for the purposes of the

present invention. Each transceiver 27, 28 is preferably configured so that its operation can be controlled by control processor and master

processor, 46 and 47, respectively.

FIG. 4 shows a single sector omni directional type wireless repeater

system, it being understood that the invention is not so limited. In fact, a

variety of sectorized repeaters can also be used for this purpose. Signals

from mobile transceivers 18 are received at omni-directional antennas

1 1 A and/or 1 1 B attached to ground sector transceiver 27. These signals

are encoded and transmitted by mobile transceivers 18 using a standard

wireless telephony format such as GSM and are typically received by

repeaters 12 in a power range from between about -1 1 1 to -25 dBm.

Received signals pass through cavity filter 29A on to

downconverter 35A or, alternatively, 35B where, in conjunction with

synthesizer module 36A and voltage-controlled crystal oscillator 37A, the

signal is mixed down to intermediate frequency or IF. A high-speed

analog-to-digital converter 39A (or 39B) then converts the analog IF signal

into a digital signal. Once the IF signal is digitized, digital downconverter

41 A (or 41 B) translates the signal down to complex baseband. Digital

downconverter 41 preferably provides the ability to downconvert,

decimate, filter and control the gain of the signal. After being converted

to complex baseband, the signal is demodulated by digital signal

processor 42A. Digital signal processor 42A is configured for decoding

the received signal data from the standard wireless telephony format,

such as GSM, to a common format used internally within the translator. The common format data is then transferred to digital signal

processor 42B in the backhaul transceiver 28 over multi-channel buffered

serial port 32. Subsequently, the signal is re-modulated by digital signal

processor 42B. The re-modulated signal is output as a complex baseband

signal and translated to real IF by digital upconverter 40B. After the

signal is translated to real IF, digital-to-analog converter 38C (or 38D)

converts the signal back to an analog signal where it is mixed by

upconverter 34B in conjunction with synthesizer module 36B and voltage-

controlled crystal oscillator 37B. Now ready to be broadcast, the signal

passes through cavity filter 29B and is transmitted through the backhaul

channel to the BTS through repeater directional antenna 1 3.

The transceivers 27 and 28 are preferably controlled by one or

more control circuits. The control circuits can be in the form of general

purpose computer interfaced with the transceiver, a programmable

microprocessor integrated with the transceivers with appropriate

software, a hardware based controller, or any other combination of

microprocessors, electronic circuitry and programming as may be

necessary or appropriate for controlling the first and second transceivers.

As shown in FIG. 4, the control circuits include master processor

47 and control processor 46. Master processor 47 preferably controls the

operation of backhaul transceiver 28, including selection of transmit and

receive frequencies. Master processor 47 is also linked with PCM data

and message bus 31 so that it can communicate with control processor

46, and vice versa. Control processor 46 is preferably a slave processor controlled by master processor 47. Control processor 46 can also

preferably control the operation of ground sector transceiver 27, including

selection of transceiver receive and transmit frequencies.

Translation of the signals transmitted from BTS 1 5 through the

backhaul channel is similar to the procedure employed to translate signals

transmitted from the mobile transceivers 18. Specifically, a signal,

preferably at -70 dBm but typically ranging anywhere from -1 1 1 dBm

to -25 dBm, is received from a BTS 1 5 at repeater directional antenna 13

attached to backhaul transceiver 28. The signal passes through cavity

filter 29B to downconverter 35C where, in conjunction with synthesizer

module 36B and voltage-controlled crystal oscillator 37B, the signal is

mixed down to IF. Analog-to-digital converter 39C converts the analog IF

signal to a digital signal where it is subsequently processed by digital

downconverter 41 C to complex baseband. The receive channel consisting

of downconverters 35D, A/D 39D and DDC 41 D are not required in this

embodiment of the invention.

Once converted into complex baseband, the signal is demodulated

by digital signal processor 42B and transferred to digital signal processor

42A over multi-channel buffered serial port 32. The signal is then re-

modulated by digital signal processor 42A and translated from complex

baseband to real IF by digital upconverter 40A. After the signal is

translated to real IF, digital-to-analog converter 38A (or 38B) converts the

signal back to an analog signal. Upconverter 34A, synthesizer 36A, and

voltage-controlled crystal oscillator 37A operate together to mix the signal for transmission. The signal is then amplified by high-power amplifier 30,

filtered by cavity filter 29A and transmitted from omni-directional antenna

1 1 A to the mobile transceiver 1 8 through the ground link channel 20-2.

Referring now to FIG. 5, a broadband BTS 1 5 is illustrated, which

comprises a receiver section 56 and a transmitter section 55. It will be

readily appreciated by those skilled in the art that the particular

transceiver architecture shown is not critical. Accordingly, the invention

disclosed herein is not intended to be so limited. Receiver section 56

preferably includes antennas 68, 70 and a wideband receiver 51 capable

of receiving a plurality of carrier frequency channels. Signals from the

received channels can include new power requests, power adjustment

requests and traffic channel data from mobile transceivers 1 8. The term

wideband, as used herein, is not limited to any particular spectral range,

and it should be understood to imply a spectral coverage of multiple

frequency channels within the communication range over which a

wireless communication system may operate (e.g. 1 2 MHZ).

Narrowband, on the other hand, implies a much smaller portion of the

spectrum, for example, the width of an individual channel (e.g. 30 kHz).

The output of the wideband receiver 51 is down-converted into a

multi-channel baseband signal that preferably contains the contents of all

of the voice/data carrier frequency channels currently operative in the

communication system or network of interest. This multichannel

baseband signal is preferably coupled to high speed A-D converters 52-1

and 52-2 operating in parallel for diversity receive capability. Where no diversity capability is required, a single A-D 52-1 could be utilized.

Additionally, more than one parallel leg may be required for sectorized

applications. Hence, it should readily be appreciated by one skilled in the

art that the presence of a second parallel processing leg is not intended to

be a limitation on the instant invention. The dynamic range and sampling

rate capabilities of the A-D converter are sufficiently high (e.g. the

sampling rate may be on the order of 25 Mega-samples per second (Msps)

to enable downstream digital signal processing (DSP) components,

including Discrete Fourier Transform (DFT) channelizers 53-1 and 53-2, to

process and output each of the active channels received by receiver 56.

The channelized outputs from the A-D converters 52-1 and 52-2

are further processed to extract the individual channel components for

each of the parallel streams. FFT channelizers 53-1 and 53-2 extract

from the composite digitized multichannel signals, respective narrowband

carrier frequency channel signals. These narrowband signals are

representative of the contents of each of the respective individual carrier

frequency communication channels received by the wideband receiver 51 .

The respective carrier frequency channel signals are coupled via N output

links through a common data bus 61 to respective digital signal

processing receiver units 63-1 ...63-2N (63), each of which demodulates

the received signal and performs any associated error correction

processing embedded in the modulated signal. In the case where the

received signals are destined for the PSTN, these demodulated signals derived from the digital signal processing receiver units 63 can be sent via

a common shared bus 54 to a telephony carrier interface, for example,

T1 carrier digital interface 62, of an attendant telephony network (not

shown) .

The transmitter section 55 includes a second plurality of digital

signal processing units, specifically, transmitter digital signal processing

units 69-1 . . . 69-N, that are coupled to receive from the telephony

network respective ones of a plurality of channels containing digital

voice/data communication signals to be transmitted over respectively

different individual carrier frequency channels of the multichannel

network. Transmitter digital signal processing units 69 modulate and

perform pre-transmission error correction processing on respective ones of

the plurality of incoming communication signals, and supply processed

carrier frequency channel signals over the common bus 54 to respective

input ports of an inverse FFT-based multichannel combiner unit 58. The

combiner 58 outputs a composite multichannel digital signal. This

composite signal is representative of the contents of a wideband signal

which contains the respective narrowband carrier frequency channel

signals output from the digital signal processing transmitter units 69. A

composite signal generated from the output of the multichannel combiner

unit 58 is then processed by the digital-to-analog (D-A) converter 59. The

output of D-A converter 59 is coupled to a wideband (multichannel)

transmitter unit 57, which can include or have a separate multi-channel

high power amplifier (HPA) 57A. The transmitter unit 57 transmits a wideband (multichannel) communication channel signal defined by the

composite signal output of the inverse fast Fourier transform-based

combiner unit 58. The output of the HPA 57A is then coupled to antenna

68 for transmission.

A central processing unit (CPU) controller 64 is provided for

coordinating and controlling the operation of BTS 1 5. For example, the

CPU 64 can include a control processing unit, memory and suitable

programming for responding to transmit power control requests received

from mobile transceiver units. CPU 64 can selectively control transmit

power levels of each TDM communication channels on a timeslot-by-

timeslot basis. The CPU 64 may be a microprocessor, DSP processor, or

micro controller having firmware, software or any combination thereof.

DSPs 63 can extract information from each of the narrowband

carrier frequency channel signals. Information for each of these channels

can be stored in shared memory 75 through the common control and data

bus 61 . CPU 64, under firmware and/or software control, can then access

the shared memory 75 through bus 61 . For example, control channel data

concerning a particular downlink or control channel can be received at

antenna 70 from a repeater 1 2 through a backhaul communication link.

After the information for each channel in the received signal is processed

and separated, DSPs 63 can store the control channel data in the shared

memory 75. CPU 64 can then access shared memory 75 to retrieve the

control channel data. CPU 64, under software and/or firmware control,

can then use this data, for example, as an input to a control algorithm. The output from the algorithm can be stored in shared memory 75 for

later use.

Referring now to FIG. 6, a flowchart illustrating an embodiment of

a method for automatically managing mobile transceivers 1 8 and

allocation of channels in a wireless repeater system is described. In step

61 0, a signal from a mobile transceiver station 1 8, is transmitted over an

uplink channel 20-1 . This signal is then received at a serving repeater 1 2,

as shown in step 620.

The power level of the signal received from the mobile transceiver

1 8 is measured at the repeater 1 2 as shown in step 630. An indication of

this measured signal power level along with the traffic information from

the received signal is then sent over a uplink channel 1 9-1 on a backhaul

communication link 1 9.

In step 640, the backhaul communication link signal 1 9 is then

received at a serving home BTS, for example, BTS 1 5. The BTS 1 5, on

receipt of the indication of the measured power level, can then send the

power indication to a managing base station controller 1 7 as shown in

step 650. The managing base station controller 1 7 can then use this

indication of the received power level at the repeater 1 2 to more

efficiently manage the mobile transceiver units 1 8 and to better allocate

channels within the system. This is illustrated in step 660.

In accordance with the invention and with reference to the

exemplary repeaters 1 2 as illustrated in FIG. 4, step 630 is now described

in detail. Repeater 1 2 receives communication signals originating from mobile transceiver unit 1 8 at antennas 1 1 A, 1 1 B from an uplink channel

20-1 . The power level of the received signal is measured at the repeater

station 1 2. One skilled in the art will appreciate that algorithms for

measuring the power level, signal strength, or bit error rate (BER) of a

signal are well known within the art. These algorithms may be performed

through the use of hardware, software or firmware, or any combination

thereof. Pertaining to the instant invention, control processor 46 may be

used to run these power measurement algorithms.

Signals from the mobile transceivers 1 8 are received at antenna

1 1 A, 1 1 B and processed by the ground sector transceiver 27. During

processing, the signals are translated down to baseband and then

demodulated. A DSP such as DSP 42A can be configured to decode the

received signal data including the traffic portion of the received signal.

The indication of the power level resulting from the power level

measurement algorithm may be passed from the control processor 46 to

the DSP 42A. The output of the measurement algorithm is encoded and

formatted by processor 46 or DSP 42A so as to conform to the common

format used internally within the repeater 1 2.

The traffic and measurement data can subsequently be transferred

via the multichannel buffered serial port 32 to DSP 42B located within the

backhaul transceiver 28. The backhaul transceiver 28 can process the

data containing the indication of the power level and the traffic portion of

the signal. The resulting signal can then be transmitted via antenna 1 3 over the backhaul communication link 1 9 on an uplink communication

channel 1 9-1 .

In one embodiment of the instant invention, the backhaul

communication link 1 9 can contain at least one traffic channel and one

control channel. The control channel may be used to transmit the

indication of the power level from the repeater station 1 2 to the BTS 1 5

via the backhaul link 1 9. The traffic channel can carry the traffic portion

of the signal received from the mobile transceiver 1 8.

An uplink TDM frame 21 conforming to the GSM recommendations

is illustrated in FIG. 3a. TDM frame 21 contains more than one TDM

channels. Slot 0 is a control timeslot and contains 8 subslots, each

representing a different control channel, of which 2 are shown. The

SDCCH 23-1 and the RACH 23-2 are control channel sub-slots within slot

0. The indication of the power level could be transmitted within one of

these control timeslots of slot 0. For example, the indication of the

power level could be transmitted within the SDCCH 23-1 or the RACH

23-2.

In one embodiment of the instant invention, the repeater 1 2

demodulates signals received from mobile transceivers 1 8 as illustrated in

step 631 a of FIG. 7. The measured power level is then encoded as

shown in step 632a. The encoded power level is then combined with the

demodulated signal containing the traffic portion of the received signal as

shown in step 633a. In step 634a, a combined signal containing the

encoded power level along with the traffic information of the received signal is then transmitted from the repeater station 1 2 over a backhaul

communication link 1 9.

For example, as shown in FIG. 3a, timeslot 4 is a typical data

timeslot that can be used to transfer traffic data. Slot 4 contains 8

subslots, 22-1 to 22-8. Other timeslots can be use to transfer traffic data

and timeslot 4 is only used for illustrative purposes. Traffic information

can be placed in subslots 22-2 and 22-6. Hence, the indication of the

power level could be transferred within subslots 22-2 or 22-6. For

example, if there is an empty uplink data timeslot available on the

backhaul channel, the encoded power level for one or more traffic

channels could be placed in that timeslot. Alternatively, the measured

power level data and traffic data for a timeslot can be compressed and

transmitted within a single timeslot assigned to a particular mobile unit.

Alternatively, since each traffic channel contains a low rate Slow

Associated Control Channel (SACCH) which is used to transport non¬

urgent signaling information, such as radio measurements used for

handover decisions, the encoded power level could be placed in the

SACCH timeslot.

Alternatively, the encoded power level could also be transmitted

over the Fast Associated Control Channel (FACCH) . Although a

misnomer, the FACCH is not an actual control channel although it

functions as one. The FACCH is actually part of the traffic channel

(TCH), wherein certain timeslots from the dedicated data slots are

"stolen" to communicate certain signaling information. Since a portion of the TCH is being stolen and used to carry this signaling information, a

stealing flag is used to indicate to a receiver the portions of the TCH that

contains the FACCH. Hence^', the stealing flag would be used to identify

the encoded power level to a receiver.

In accordance with the spirit of the invention and with reference to

the exemplary BTS 1 5 as illustrated in FIG. 5, steps 640 and 650 are now

described in detail. A multichannel signal over the backhaul

communication link including measured received power level information

as received at repeater 1 2 from mobile transceiver unit 18 can be

transmitted to antennas 68,70 and processed by receiver 56. Wideband

receiver 51 processes.the multichannel signal and extracts the individual

narrowband channels contained in the signal. Each narrowband signal is

coupled to one of N respective DSP receiver processing unit 63-1 to

63-2N. Each carrier signal is demodulated and the necessary error

correction scheme performed on the demodulated information. Error

correction schemes, such as Forward Error Correction (FEC), are well

known in the art. For example, U.S. Patent Number 5,896,391 to

Solheim et al, titled "Forward Error Correction Assisted Receiver

Optimization, " describes a FEC methodology. The resulting contents of

each channel can then be stored in memory within the DSP 63. The

channel containing the power level information could then be stored in the

memory associated with DSPs 63-1 .

Alternatively, under the control of CPU 64, the contents of each

channel can be stored in the shared memory 75 via the common bus 61 , thereby giving other peripherals access to the stored information. The

CPU 64 can then access the shared memory 75 and manipulate the

information for each channel. In this case, the power level indication

would be stored in the shared memory 75. Once the channel containing

the indication of the measured power level is demodulated and stored in

memory, this information may be transferred to the associated memory of

DSP 69 for transmission to the managing base station controller (BSC),

for example, BSC 17.

In yet another embodiment of the instant invention, and with

reference to FIG. 8, the flowchart illustrates a method for selectively

controlling the output power level on a backhaul communication link 19.

The power level of the signal received from a mobile transceiver 18 is

measured by control processor 46 or repeater 12 through the use of

algorithms that are well known in the art. Control processor 46 can

convert the result of the algorithm to a digital representation as shown in

step 631 b.

Using control processor 46, repeaters 12 can maintain a lookup

table corresponding to a range of possible values that can be returned

from the measurement algorithm along with a corresponding output

power level that can be used to control the transmitter for the backhaul

communication link 19 for each of the received power ranges. The

lookup table may be stored in non-volatile memory for permanent storage.

Alternatively, the lookup table may be stored in, non-volatile memory,

such as static RAM, where the corresponding output power level for transmission on the backhaul communication link 1 9 can be continuously

updated depending on the conditions that exist on the uplink channel 19-1

of the backhaul communication link 1 9.

Using control processor 46, the repeater 1 2 may consult the

predefined lookup table stored in memory and compare the digital

indication of the signal power level measurement to the predefined ranges

to determine the range in which the digital indication of the signal power

level falls. This is shown in step 632b. Once the range is determined,

the control processor 46 can then extract from the lookup table stored in

memory, the corresponding predetermined output power that the

transmitter should preferably use for transmission on backhaul

communication link 1 9. This is illustrated in step 633b. Once the

predetermined transmission output power level is determined by processor

46, processor 46 can then send instructions to the backhaul transceiver

28 to transmit signals over the uplink channel 1 9-1 of the backhaul

communication link 1 9 at the specified transmission power. This is

shown in step 633c.

With reference to figure 9, and in accordance with the spirit of the

invention, an exemplary lookup table is illustrated. The table described

therein is intended for illustrative purposes and therefore, it is not

intended to limit the invention in any manner. The following example

illustrates how the transmitted power level on the backhaul

communication link 1 9-1 can be controlled using the exemplary lookup

table. After running the received power level measurement algorithm,

processor 46 gets a digital indication of the power level measurement that

can be, for example, equivalent to -68 dBm. In response, processor 46

would then access the lookup table stored in memory as a suitable data

structure and find the appropriate range within which the measurement

falls. For a -68 dBm received signal, the lookup table range is from -66

dBm to -75 dBm. Once processor 46 locates the appropriate input power

range, it then can extract the corresponding predetermined output power

level of -70 dBm. Processor 46 can then send an instruction to the

backhaul transceiver 28 to transmit signals over the uplink channel of the

backhaul communication link 19-1 at a power level of -70 dBm.

Claims

CLAIMSWhat is claimed is:

1 . In a wireless cellular communication system having a base

transceiver station located within a home cell and a plurality of

substantially adjacent cells each having a repeater located therein, a

method for managing a plurality of mobile transceiver units, comprising:

receiving at one of said repeaters, a signal from a mobile

transceiver unit on an uplink communication channel;

measuring at said repeater a power level of said signal as

received by said repeater; and

transmitting a backhaul signal from said repeater to said base

transceiver station on a backhaul communication link, said backhaul signal

including at least an indication of said power level as measured by said

repeater.

2. The method according to claim 1 , wherein said backhaul

communication link is comprised of at least one traffic channel and one

control channel and said indication of said power level is transmitted on

said control channel.

3. The method according to claim 2, wherein said control channel is at

least one of a random access channel (RACH) and a dedicated control

channel (DCCH) .

4. The method according to claim 1 wherein said backhaul

communication link is comprised of at least one time division multiplex

(TDM) channel and said indication of said power level is transmitted on at

least one of said time division multiplex channels.

5. The method according to claim 1 , wherein said indication of said

power level is digitally encoded within said backhaul signal.

6. The method according to claim 5, further comprising:

generating a power level data which is a digital

representation of said signal power level as measured at said repeater;

demodulating said signal from said mobile transceiver unit;

formatting said power level data and said signal as

demodulated for transmission; and

modulating said power level data as formatted and said

signal as demodulated for transmission over said backhaul communication

link.

7. The method according to claim 6, wherein said power level data is

transmitted within a control channel (CCH).

8. The method according to claim 6, wherein said power level data is

transmitted within a traffic channel (TCH).

9. The method according to claim 1 , further comprising selectively

controlling a backhaul signal transmitted power level to indicate said

power level of said signal received from said mobile transceiver unit.

10. The method according to claim 9, wherein said selectively

controlling a backhaul signal transmitted power level further comprises:

generating power level data which is a digital representation

of said power level as measured at said repeater;

correlating said power level data to a predetermined

transmitter power level associated with said power level; and

controlling a transmitter of said repeater to transmit at said

predetermined transmitter power level.

1 1 . The method according to claim 1 0, wherein said base transceiver

sation (BTS) assigns channels in said wireless communication system

based on said indication of said power level.

1 2. A wireless cellular communication system having a base transceiver

station located within a home cell and a plurality of substantially adjacent

cells each having a repeater located therein, said wireless cellular

communication system, comprising:

receiving means for receiving at one of said repeaters, a

signal from a mobile transceiver unit via an uplink communication channel; power measurement means for measuring at said repeater a

power level of said signal as received by said repeater; and

a transmitter means for transmitting a backhaul signal from

said repeater to said base transceiver station via a backhaul

communication link, and for including in said backhaul signal at least an

indication of said power level as measured by said repeater.

13. The wireless communication system according to claim 12,

wherein said backhaul communication link further comprises:

at least one traffic channel for sending said traffic portion of

said signal; and

at least one control channel for sending said indication of

power level as measured by said repeater.

14. The wireless communication system according to claim 13, wherein

said control channel is at least one of a random access channel (RACH)

and a dedicated control channel (DCCH).

1 5. The wireless communication system according to claim 12, wherein

said backhaul communication link is comprised of at least one time

division multiplexed (TDM) channel and said indication of said power level

is transmitted on at least one of said time TDM channels.

16. The wireless communication system according to claim 13, further

comprising encoding means for digitally encoding said power level as

measured at said repeater.

17. The system according to claim 16, further comprising:

demodulator means for demodulating said signal from said

mobile transceiver unit;

means for formatting said power level as digitally encoded

and said signal from said mobile transceiver unit as demodulated; and

means for transmitting said power level as formatted and at

least a portion of said signal as demodulated for transmission over said

backhaul communication link.

18. The wireless communication system according to claim 16, wherein

said .power level as encoded is placed in a control channel (CCH).

1 9. The wireless communication system according to claim 1 6, wherein

said power level as encoded is placed in a traffic channel (TCH).

20. In a wireless cellular communication system having a base

transceiver station located within a home cell, a plurality of substantially

adjacent cells each having a repeater located therein, a method for

automatically controlling power level in a backhaul communication link,

said link having at least one channel, the method comprising: receiving at one of said repeaters, a signal from an uplink

channel;

measuring at said repeater, a signal power level of said signal

as received by said repeater;

transmitting an indication of said signal power level received

by said repeater on said backhaul communication link;

receiving at a base transceiver station, said indication of said

signal power level; and

assigning channels in said wireless communication system at

said base station, based on said signal power level.

21 . The method of claim 20, wherein said signal from an uplink channel

received at one of said repeaters is from a mobile transceiver signal.

22. The method of claim 20, wherein said signal from an uplink channel

received at one of said repeaters is from a pilot signal.