HK1004971A - Self-adjusting rf repeater arrangements for wireless telephone systems - Google Patents

Description

Self-adjusting RF repeater for wireless telephone system

Technical Field

The present invention relates to repeaters for wireless telephone systems, and more particularly to repeaters for linking base stations and mobile wireless handsets in such systems, which are suitable for both Time Division Duplex (TDD) signals and Frequency Division Duplex (FDD) signals.

The present invention may be used in a wireless telephone system that employs signal conduits (e.g., coaxial cables, optical cables, microwave relay links, infrared links, cable television lines, or a combination of two or more thereof) to link a set of radio frequency repeater units (e.g., microcell extenders) with a base station.

Background

The base station is used to interface the switched telephone network with radio frequency signals, that is to say the base station transmits and receives radio frequency signals to and from the radio telephone network. A base station may generally support voice links for multiple networks.

The base station has radio frequency signal transmitting and receiving means and control means and may be connected via coaxial cable or other signal conduit to one or more radio frequency repeaters which interface with the handsets, i.e. broadcast to and receive radio signals from the base station in the form of radio signals, and transmit them to the base station. Thus, the RF repeater can be used to expand the actual service area of a base station.

In many cases it is suitable to make such a radio frequency repeater as an arrangement of two radio frequency repeater parts or units, namely a first part or base station extender for interfacing with a base station and a second part or microcell extender for interfacing with a handset. The two parts may in practice be separated by a long distance, for example several kilometres, and connected by a signal conduit, for example in the form of a coaxial cable or an optical cable.

In practice, the second part of the rf repeater or handset part is often a number of such handset interfaces located at different sites, which are commonly connected to the first or base station interface part. This results in a radio frequency repeater that enables a single base station to serve several different sites.

One problem with existing rf repeater technology is the need to provide the second part of the rf repeater with timing and level adjustment information regarding its particular location in the signal conduit network. For example, if the second portion of the rf repeater were connected to the first portion of the rf repeater via a 100 meter coaxial cable, the received signal level would be attenuated by the 100 meter coaxial cable, but the loss factor over the length of the coaxial cable would be significantly different from that encountered by the second portion of another rf repeater connected via a 200 meter coaxial cable. In order to be able to transmit the correct signal level, it is necessary to determine and compensate for the respective specific loss factor of the second part of each rf transponder.

This problem can be solved in several different ways: 1. the gain of the second part of each rf repeater may be adjusted manually. In a large network, this approach is not desirable and in any case is inefficient because it is difficult to set the transmit power of the handset interface when there is a set of transmit signals unless the rf insertion loss is known.

In addition, when using a cable television network as a signal pipe, the losses of the user taps and splitters constitute a part of the overall radio frequency loss. Since the losses associated with such devices are typically generated in the user's house, they are not readily ascertainable from the outdoors.

The required gain also varies as a function of time, temperature, etc. 2. A pilot signal may be inserted in the first part of the rf repeater for conventional automatic level control. This approach provides a general solution, but is often undesirable because the insertion of the pilot signal increases the probability of spurious signals being emitted from the rf repeater. This is because if the pilot signal is lost on the signal pipe the same as the radio frequency signal, its frequency must be close to the radio frequency signal frequency.

In some signal pipes (e.g., cable television networks), increased complexity is required to obtain a frequency band suitable for the pilot signal. 3. A conventional automatic level control system can be established on the basis of the base station radio frequency transmission signal as a pilot signal. This approach is useful in some cases, particularly when the rf signal conforms to a single carrier Time Division Multiple Access (TDMA) format, but is not suitable when other formats are used, such as multi-carrier TDMA or frequency division multiple access (TDMA). 4. Some radio frequency signaling protocols (e.g., CT-2 plus) have a Control and Signaling Channel (CSC) or similar beacon that can be used as a reference level. CSCs are not defined for this use. They may not be present during a voice link or may change levels in an adaptive power control environment in a manner that is inconsistent with their use as reference levels.

In the above example, the problem is discussed in terms of transmit power levels. The same problem exists with the received power level. The second portion of the group of rf repeaters works best if the measured receive path gain returned to the base station by each of the second portions of the rf repeaters via the respective signal pipe connections is the same.

Summary of The Invention

It is therefore an object of the present invention to provide a new and improved rf repeater for linking a base station and a wireless handset, wherein the transmit and receive signal levels of the rf repeater are adjusted to compensate for rf insertion loss on the signal path between the handset interface portion thereof and the base station interface portion of the wireless repeater.

The present invention provides an RF repeater for linking a base station and a handset in a wireless telephone system, which includes a first RF repeater part linked with the base station, a second RF repeater part transmitting and receiving wireless signals to and from the wireless handset, and a signal pipe connecting the first and second RF repeater parts.

The first rf repeater section includes a signal level detector for measuring the power of the transmitted signal from the base station. The measurements of radio frequency transmit power from the base station are quantized at the first radio frequency repeater portion and output as data on a control channel, e.g., 10.7Mhz, used for communication between the first and second radio frequency repeater portions. Because the control channel is not used as a pilot signal per se, it may be multiple octaves of the radio frequency signal and therefore may not create spurious emissions or other difficulties.

The base station is usually provided with internal level control so that it can be ensured that a known output level is provided per carrier. It should be noted that multi-carrier TDMA base stations and FDMA base stations change the current number of carriers according to the requirements of voice traffic. The effective power output from the base station (i.e., the sum of the individual carrier powers) in such a system may vary, making the radio frequency signal unsuitable for use as a pilot signal.

The second radio frequency repeater section demodulates the control channel to restore radio frequency level information. This information is then compared to the signal level detector output located within the second radio frequency repeater portion. The signal level adjuster of the second rf repeater section adjusts to increase the transmission signal level of the second rf repeater section to a predetermined ratio of the transmission signal level of the first rf repeater section based on the comparison. The second rf repeater section can correctly adjust its own level despite the changes in the effective rf level from the base station in multi-carrier TDMA and FDMA systems.

By using a predetermined offset in the second rf repeater portion, the receive path gain can be obtained from the transmit path gain information.

For a TDD system, the transmit path gain and the receive path gain are the same for non-heterodyne signal transmission over the signal pipe, and thus the second rf repeater portion may use this gain adjustment method for both transmit and receive path gain adjustments.

For some TDD systems (e.g. CT-2Plus using TDD-FDMA technology or DECT using TDD-TDMA technology), the base station provides regular, level and regular radio frequency bursts (e.g. CSC channel in CT-2Plus system or beacon signal in DECT system) so that the first radio frequency repeater clearly identifies these bursts. In this case, the transmit-receive timing relationship may be derived from a signal level detector used to make level measurements at the first rf repeater portion.

For TDD systems, primary timing information may also be provided.

Brief Description of Drawings

The present invention will be more clearly understood to those skilled in the art from the following description of the embodiments with reference to the accompanying drawings. The drawings are as follows:

FIG. 1 shows a block diagram of a wireless telephone system;

fig. 2 shows a block diagram of a base station extender forming part of the telephone system of fig. 1;

figure 3 shows a block diagram of a microcell extender forming part of the telephone system of figure 1;

figures 4a and 4b show an amplifier forming part of the microcell extender of figure 3 (when supporting TDD signals) and a change-over switch for two different switching modes;

FIG. 5 shows an improvement to the telephone system of FIG. 1;

figure 6 shows a modification to the microcell extender of figure 3 for a frequency division multiplexed system;

figure 7 shows a block diagram of an amplifier forming part of the microcell extender of figure 6.

Description of the remaining modes

Fig. 1 shows a telephone system comprising a base station 10 for interfacing with a public switched telephone network (not shown), more particularly a base station which receives baseband transmission signals from the public switched telephone network and outputs them as Time Division Duplex (TDD) or Frequency Division Duplex (FDD) transmission signals; in addition, the received signals to TDD or FDD are converted into baseband signals to be sent to the public switched telephone network. Such base stations are well known in the art and will not be described in further detail herein.

The base station 10 is connected to a radio frequency repeater which, in embodiments of the invention, comprises a first radio frequency repeater section in the form of a base station expander (BEX) connected by signal conduits in the form of coaxial cables 14 and 16 to a second radio frequency repeater section in the form of mini cell expanders (MEX)18 and 19 having an antenna 20 for exchanging transmit and receive signals in the form of radio signals with a mobile radio handset 22.

The advantage of the above described rf repeater is that if the handset 22 is within the coverage area of the microcell extenders 18 or 19, only one base station 10 is required to exchange transmit and receive signals with the handset 22, and therefore the use of two microcell extenders 18 and 19 expands the effective coverage area of the base station 10. It will be apparent to those skilled in the art that the telephone system is not limited to the use of only two microcell extenders 18 and 19 and may include a plurality of microcell extenders having overlapping coverage areas to form a roaming path through which the handset 22 may roam when communicating with the base station 10.

However, due to the different lengths of the coaxial cables 14 and 16, the attenuation experienced by the transmit signals attenuated by the coaxial cables 14 and 16 and the base station extender 12 and microcell extenders 18 and 19 is not the same, corresponding to different signal level losses between the base station extender 12 and microcell extenders 18 and 19. Inserting a radio frequency splitter to form, for example, a sub-network of microcell extenders off of the coaxial cable 16, may exacerbate this asymmetry in attenuation loss. Likewise, the received signal transmitted from the antenna 20 to the base station 10 is subject to different attenuations. The present invention provides means to compensate for these signal losses, as described below.

Referring now to fig. 2, which illustrates the base station extender 12 in more detail, the connector 24 connected to the base station 10 is connected via a dc blocking capacitor 26, a high pass filter 28 and a second dc blocking capacitor 30 to a splitter 32, the splitter 32 having two coaxial cable connectors 34 for connecting the coaxial cables 14 and 16.

For example, when the telephone system operates according to the CT-2PLUS standard (TDD-FDMA), the base station will output a 1 millisecond transmit signal at 944MHz and receive a 1 millisecond receive signal at 944 MHz. The transmitted signal level of the base station 10 is typically high, e.g. 10mW, while the received signal power level is typically low, e.g. 1 nW.

The base station extender 12 also has a power input line 36 connecting an ac power source (not shown) to a power source 38, the power source 38 outputting dc or low frequency ac power through the splitter 32 to the core of the coaxial cable 34 to drive the remote microcell extenders 18 and 19.

A directional coupler 40 is connected between the dc blocking capacitor 26 and the high pass filter 28 and directs a portion of the base station transmit signal to a first signal level detector 42 comprising a standard diode detection circuit. Whenever the base station transmits a 1 millisecond signal, the signal level on the detector 42 produces a 1 millisecond pulse whose height is proportional to the amplitude of the transmitted signal from the base station 10. The pulses are fed to a microprocessor controller 44 which, as described in more detail below, quantizes and encodes the pulse heights into signal level data representing the pulse heights in a data stream that is modulated onto a 10.7MHz subcarrier by a Frequency Shift Keying (FSK) modulator. The modulated signal level data is then passed through a low pass filter 48 to a directional coupler 50 connected between the high pass filter 28 and the dc blocking capacitor 30 for transmission over the coaxial cables 14 and 16 to the microcell extenders 18 and 19. In an embodiment of the present invention, the microprocessor controller 44 is implemented by a Motorala 68HCll microprocessor with an on-chip analog-to-digital converter.

It should be noted that the directivity of the directional coupler 40 is advantageous for detecting the transmitted signal from the base station 10 and for detecting the received signal from the handset 22. This directionality, coupled with the difference in the transmitted and received signals, makes it easy for the microprocessor controller 44 to distinguish between the transmitted and received signals. The microprocessor controller 44 is able to determine the transmit/receive timing required for synchronization of the second rf repeater portion using the level detector 42 since the transmit signal pulse and the receive pulse can be identified. This method of deriving the timing of the transmission and reception is only useful when the handset has established a signal link with the base station (i.e. a valid transmission burst from the base station is detected). It is generally not suitable for situations where there is no base station-handset link.

When no such link exists, the CSC or beacon signal from the base station may be used to provide timing. Thus, for example, in the CT-2plus protocol, a standard radio burst signal (CSC) from the base station is guaranteed when no base station-handset link is present. Thus, for CT-2plus, the CSC, when used with the timing derived during the voice connection, can provide full transmit receive timing during all signal occurrences.

The microprocessor controller 44 encodes transmit-receive timing information into the FSK data stream.

The microcell extender 18 is shown in more detail in the block diagram of figure 3 and is intended to operate in TDD mode using the CT-2plus protocol, it being understood that the microcell extenders 18 and 19 are identical to each other.

As shown in fig. 3, the picocell extender 18 has an input in the form of a coaxial cable connector 52 connected to the coaxial cable 14. The coaxial cable connector 52 is connected to the input of a band (width limited) TDD amplifier 62 through a dc blocking capacitor 54, a directional coupler 56, a high pass filter 58 and a variable attenuator 60. As described below, the variable attenuator 60 and the amplifier 62 constitute a signal level adjuster that adjusts the levels of the transmission and reception signals. The output of the band-limited TDD amplifier 62 is connected to the antenna 20 through a directional coupler 64 and the output of the microcell extender 18.

The coaxial cable connector 52 is also connected to a dc switching regulator 64, the output of which provides dc power to all of the electronic circuits of fig. 3.

Directional coupler 56 passes a portion of the input signal from coaxial cable 14 through a low pass filter 66 best suited for passing 10.7MHz signals to a 10.7MHz frequency shift keying demodulator 68 whose output contains signal level data and transmit-receive synchronization data provided by base station extender 12 as described above.

A portion of the output of the band-limited TDD amplifier 62 is fed by the directional coupler 64 to a second level detector 70 which detects the power level of the transmitted signal amplified and applied to the antenna 20 and provides this level to control means in the form of a microprocessor controller 72.

The level detector 70 is implemented by a circuit similar to the level detector of fig. 2, i.e. a standard diode detection circuit. This can often reduce temperature, tolerance and linearity constraints, as the use of the same level detectors 70 and 42 will generally remove these distortions.

The signal level data from the demodulator 68 is output to the microprocessor controller 72 for comparison with the quantised levels from the level detector 70 to determine the difference between the transmitted signal levels at the base station extender 12 and the microcell extender 18, and the microprocessor controller 82 adjusts the variable attenuator 60 accordingly to maintain a specific ratio, for example 1: 1, of the amplified transmitted signal level to the antenna 20 to the transmitted signal level measured by the level detector 42 of figure 2.

The microcell extender will adjust its output, for example, so that the signal level at the antenna 20 is substantially equal to the signal level output by the base station 10. The same is true of the transmitted signal level at the antenna 20 of the microcell extender 19.

Directional coupler 64 advantageously provides transmit signal power to power detector 70, but does not facilitate the transfer of receive signal power.

Referring now to fig. 4a and 4b, there is shown in more detail the band-limited time division duplex amplifier 62 comprising a pair of series connected amplifiers 72 and 74, connected between the amplifiers 72 and 74 by a band-limiting filter 76. The output of amplifier 74 and the input of amplifier 72 are connected to respective terminals of a transfer switch, generally indicated by the reference numeral 78. The antenna 20 and the lead 80 extended from the variable attenuator 60 are connected to the other ends of the changeover switch 78.

The changeover switch 78 has two changeover states. As shown in fig. 4a, in a first switching state, i.e., a receiving state in which a received signal from the handset 22 is received by the antenna 20, the switch 78 connects the antenna 20 to the input of the amplifier 72, and also connects the input of the amplifier 78 to the variable attenuator 60 so that the received signal is amplified by the amplifiers 72 and 74, and the variable attenuator 60 controls the gain to counteract the attenuation between the antenna 20 and the base station.

In the second switching state of the changeover switch 78, as shown in fig. 4b, the conductor 80 from the variable attenuator 60 is connected to the amplifier 72 input and the amplifier 74 output is connected to the antenna 20. Therefore, in this transmission state, the transmission signal is attenuated by the variable attenuator 60 and then amplified by the amplifiers 72 and 74 to cancel the signal loss between the base station 10 and the antenna 20 as described above.

The change in state of the transfer switch 78 is controlled by the microprocessor controller 72 based on control outputs generated from the timing of the transmitted and received signals.

Thus, amplifiers 72 and 74 are used to amplify both the transmit signal and the receive signal, with equal transmit and receive gains. The amplifier and switching means shown in fig. 4A and 4B thus enable the microcell extender 18 to automatically compensate for the loss of the transmission signal from the base station 10 to the antenna 20 and the loss of the reception signal from the antenna 20 to the base station 10.

Fig. 5 shows an improvement to the telephone system shown in fig. 1. More specifically, in the modification shown in fig. 5, a tandem amplifier unit 90 similar to the microcell extenders 18 and 19 is connected between the base station extender 12 and the microcell extender 19 for amplifying the transmission and reception signals through the coaxial cable 16 and forwarding the amplified signals to the microcell extender 19 or the base station extender 12 as it is.

The tandem amplifier unit 90 is similar to the picocell extender 18 shown in figure 3 except that the antenna 20 is omitted and a coaxial cable connector 91 (figure 3) is substituted for connection to the coaxial cable 16A (figure 5) extending to the picocell extender 19. This arrangement allows the microcell extender 19 to be connected to the base station by a substantially longer, and therefore more lossy, coaxial cable.

As shown in fig. 3, a bypass conductor 92 with a switch 94 connects the coaxial cable connections 52 and 91, i.e. the input and output of the series amplifier unit. The switch 94 is closed to pass the 107MHz sub-carrier and power from the tap 52 to the tap 91 and thence to the microcell extender 19.

When such a series configuration is used, it is generally preferable to set the output level of the series amplifier unit 90 lower than the usual emission level. This allows the cascaded intermodulation budget (intermodulation budget) to the tandem amplifier unit 90 and the line end microcell extender to be controlled entirely by the line end performance. In operation, therefore, the microcontroller 72 detects the closure of the switch 94 and adjusts the variable attenuator 60 to ensure that the signal level measured at the junction 91 is typically one tenth of the output signal level of the base station 10. The series transmit gain is equal to the series receive gain.

As described above, the transmission and reception signals are in a time division duplex signal manner. The apparatus of figures 1, 2 and 3 described above can be readily adapted to frequency division duplex mode.

To this end, the band-limited TDD amplifier 62 of fig. 3 is replaced by a band-limited FDD amplifier 100, as shown in fig. 6. The other parts of the microcell extender shown in fig. 6 are the same as those of fig. 3 and are therefore denoted by the same reference numerals and will not be described again here.

The band limited FDD amplifier 100 of figure 6 is illustrated in more detail in figure 7.

As shown in fig. 7, conductor 60 from variable attenuator 60 is connected to duplexer 104 which passes the transmit signal through band-limiting filter 106 to transmit amplifier 108 and receives the receive signal from band-limiting filter 110 and receive signal amplifier 112 which passes the receive signal through conductor 102 to variable attenuator 60.

The output of the transmit signal amplifier 108 and the filter 110 are connected to another duplexer 114 which is connected to the antenna 20 through the directional coupler 64.

If desired, duplexers 104 and 114 may be replaced with radio frequency splitters/combiners.

In the FDD configuration, the transmit amplifier 108 and filter 106 are physically distinct from the receive amplifier 112 and filter 110. Because the transmit signal level is typically several orders of magnitude higher than the receive signal level, microprocessor controller 72 can readily distinguish between the transmit power level and the receive signal power level using power detectors 42 (fig. 2) and 70 (fig. 3). Given the gain of the receive amplifier 112 relative to the transmit amplifier 108 of fig. 7, the receive path gain between the antenna 20 and the base station 10 can also be well controlled and determined based on the signal level adjustment used to transmit the signal gain.

The operation of the microprocessor controller 44 includes the following steps: 1. the level from the detector 42 is measured. 2. If the level corresponds to a signal greater than one tenth of a milliwatt, it is considered to represent a transmitted pulse.

If the level is less than one tenth of a milliwatt, it is considered to represent a received pulse. 3. If a transmit pulse is present, the level data is sent to the FSK modulator 46 for transmission to all of the second rf repeater sections.

If a receive pulse is present, information "receive pulse present" is sent to all second rf repeater sections. 4. If a transmit pulse is present but the previous measurement indicated a received pulse, the measurement is marked as the "initial transmit pulse". 5. The "start transmit pulse" data is sent to the FSK modulator 46 for transmission to all second rf repeater sections. 6. The level measurement is repeated (i.e. return to step 1).

In the specific CT-2plus example, where there is a 1 millisecond transmit time and a 1 millisecond receive time, the FIG. 3 microprocessor controller 72 would normally operate in the following manner given this sequence: 1. data is read from the FSK demodulator 68. 2. If the read data is "start transmit pulse", the software counter is started, and 1 millisecond later the switch 78 is placed in the receive position and 2 milliseconds later it is placed in the transmit position. 3. If the data gives the transmitted signal level, the level at the present moment is read in from the level detector 70. 4. If switch 94 is closed (series mode), the signal level recorded by level detector 70 is multiplied by 10.

If the switch 94 is open (end of line mode), the signal level recorded by the level detector 70 is multiplied by 1. 5. If the level from level detector 70 is higher than the level read on demodulator 68, the attenuation at variable attenuator 60 is increased by a small increment.

If the level from 70 is lower than the level read on demodulator 68, the attenuation at variable attenuator 60 is reduced by a small increment. 6. Repeat step 1 above.

Note that at the start of power-up, these software steps may cause the rf repeater to fail to operate properly for two or three hundred milliseconds, after which it is fully normal. In practice this is not a problem.

Of course, more complex procedures may be employed. For example:

the microprocessor controller of fig. 3 may average the multiple measurements before determining when the "start fire pulse" or actual value of the fire level occurs.

As mentioned, CT-2plus provides CSC bursts when there is no voice link. The CSC includes three 1 millisecond bursts every 72 milliseconds.

In this case, if the previous "start transmit pulse" indicates that it is the transmit time, but the read level data is "receive signal present" as opposed to the previous result, the microprocessor controller 72 of fig. 2 will add the step of generating its "start transmit pulse" at step 2.

The above description of the operation of microprocessor controllers 72 and 44 is made in the TDD mode. In practice the same software may be used for FDD related level control operations, but the timing control software may be limited to use in FDD-TDMA systems only to select a particular time slot for broadcast/reception to a group member.

Various modifications may be made to the apparatus described above within the scope and spirit of the appended claims. For example, it may be useful in some cases to use heterodyne techniques in the rf repeaters of fig. 4 or 7. In addition, it is suitable in some cases to use one variable gain amplifier instead of the variable attenuator and amplifier that adjust the signal level as described above.

Claims (18)

1. A radio frequency repeater apparatus for broadcasting a transmission signal from a base station to a mobile handset and transmitting a reception signal from the handset to the base station in a wireless telephone system, comprising: a first RF repeater part interfacing with the base station, a second RF repeater part separated from the first RF repeater part and having an antenna for exchanging transmission and reception signals with the handset in the form of wireless signals, and a signal pipe connecting the first and second RF repeater parts; it is characterized in that the preparation method is characterized in that,

the first rf repeater section including a first level detector for detecting a signal level of a transmission signal of the first rf repeater section, and a modulator for modulating the detected signal level onto a carrier for transmission to the second rf repeater section through the signal pipe; the second radio frequency repeater part includes: a signal level adjuster for amplifying the transmission signal, a second level detector for detecting a level of the transmission signal amplified by the signal level adjuster, a demodulator for demodulating a level of the signal from the first rf repeater section, a controller for comparing the demodulated signal level with the signal level detected by the second level detector to provide a control output to the signal level adjuster, and an antenna for broadcasting the transmission signal to the handset; the signal level adjuster changes its gain according to the control output to increase the signal level detected by the second level detector to a predetermined ratio of the level detected by the first level detector.

2. The radio frequency repeater device as claimed in claim 1, wherein the signal level adjuster includes a switch for alternately connecting the transmission signal and the reception signal to the signal level adjuster so that gains of the amplification of the transmission and reception signals are the same.

3. The radio frequency repeater arrangement as claimed in claim 1, wherein the first radio frequency repeater part comprises a processor for quantizing and encoding the output of the first level detector, and means for obtaining the timing of the transmitted signal and the received signal from the first level detector, the modulator being controlled by the processor.

4. The rf repeater assembly of claim 1, wherein the first rf repeater portion includes a coupler for coupling the transmit signal and the receive signal to the first level detector, the coupler comprising a directional coupler that facilitates coupling the transmit signal to the first level detector to assist the processor in distinguishing the transmit signal from the receive signal.

5. The radio frequency repeater device as claimed in claim 1, wherein the controller includes means for obtaining timing from a control and signaling channel or a beacon signal from the base station when there is no base station-mobile handset link.

6. The rf repeater device of claim 1, wherein the signal level adjuster includes a switch for alternately connecting the transmit signal and the receive signal to the signal level adjuster in transmit and receive switching states, respectively, whereby the gains of the transmit and receive signal amplifications are the same, the controller including means for changing the state of the switch in accordance with the timing of its transmit and receive signals.

7. The radio frequency repeater device as claimed in claim 1, further comprising a series amplifier unit connected to the base station and the second radio frequency repeater part through signal pipes, the series amplifier includes another signal level adjuster for amplifying a transmission signal, another level detector for detecting a signal level amplified by the signal level adjuster, a demodulator for demodulating signal level data from the first RF repeater portion, a further controller for comparing the demodulated signal level data with the signal level measured by the further level detector to provide a further control output for the further signal level adjuster, the gain of the further signal level adjuster is varied in dependence on the further control output to increase the signal level detected by the further level detector to a predetermined ratio of the level detected by the first level detector.

8. The radio frequency repeater device as claimed in claim 7, wherein the another signal level adjuster includes a transfer switch for alternately connecting the transmission signal and the reception signal to the another signal level adjuster so that gains of the transmission and reception signal amplification are the same.

9. The radio frequency repeater device as claimed in claim 6, wherein the series amplifier has an input, an output, a bypass conductor path between the input and the output, and a switch in the bypass conductor path for connecting power and carrier from the input to the output.

10. The radio frequency repeater device as claimed in claim 1, wherein the second radio frequency repeater part includes a demodulator for demodulating signal level data, an amplifier for amplifying the transmission and reception signals, the signal level detector detects a transmission signal level amplified by the amplifier and a reception signal level from the antenna, the variable attenuator is connected between the signal pipe and the amplifier, the controller includes a microprocessor controller for comparing the demodulated signal level data with the transmission signal level detected by the second signal level detector and adjusting the attenuator accordingly to cancel attenuation of the transmission and reception signals on the signal pipe, the second microprocessor controller is connected to the amplifier to provide the timing from the transmission and reception signals thereto.

11. The rf repeater device of claim 10, wherein the amplifier has an input, an output and a switch controlled by timing from the second microprocessor controller to alternately connect the output to the antenna to broadcast the amplified transmission signal and the antenna to the input to amplify the received signal so that the transmission signal and the received signal undergo the same amplification.

12. The radio frequency repeater device as claimed in claim 9, wherein the directional coupler for connecting the transmit and receive signals to the first and second level detectors is configured to facilitate coupling the transmit signal to the first and second level detectors to assist the first and second microprocessor controllers in distinguishing the transmit signal from the receive signal to obtain timing information from the transmit signal.

13. A method of broadcasting to a mobile handset a transmit signal from a base station and transmitting to the base station a receive signal from the handset in a wireless telephone system, using an rf repeater comprising: a first rf repeater part interfacing with the base station, a second rf repeater part separated from the first rf repeater part, the second rf repeater part having an antenna for exchanging transmission and reception signals with the handset in the form of wireless signals, and a signal pipe connecting the first rf repeater part and the second rf repeater part, characterized in that;

detecting a transmission signal level at the first rf repeater portion, modulating the detected signal level onto a carrier for transmission to the second rf repeater portion through the signal conduit, amplifying the transmission signal at the second rf repeater portion, detecting the amplified transmission signal level, demodulating the signal level from the first rf repeater portion, comparing the demodulated signal level with the detected signal level of the second rf repeater portion to provide a control output for controlling the amplification process and broadcasting the amplified transmission signal to the handset.

14. The method of claim 13, wherein the transmit signal and the receive signal are alternately connected to the amplifier such that the transmit and receive signals are amplified with the same gain.

15. The method of claim 13, wherein timing of transmitting and receiving signals is acquired at the first rf repeater portion to synchronize the first and second rf repeater portions.

16. The method of claim 15, wherein a directional coupler is used in the first rf repeater portion to advantageously couple the transmit signals to distinguish the transmit signals from the receive signals.

17. The method of claim 13, wherein the timing is obtained from a control and signaling channel or a beacon signal from the base station when there is no base station-mobile handset link.

18. The method of claim 13, wherein the transmit and receive signals are amplified at locations between the first and second rf repeater sections based on signal levels detected by the first rf repeater section.