Abstract:
Simplified centrally located equipment for use in a wireless telephone system that uses of an existing broadband distribution network to carry telephony signals between an existing telephone network and remote transceivers sites in defined cells or sectors is disclosed. The simplification is accomplished by reducing the number of frequency translation steps between elements of the centrally located equipment by using the same carrier frequency for signal handling within the elements of the centrally located equipment as is used to transmit telephony signals between elements.

Description:
FIELD OF THE INVENTION 
     The present invention relates to wireless communications systems, and more particularly to improved centrally located equipment for a wireless telephone system that incorporates an existing broadband distribution network, such as cable television network cable, to carry communication signals between wireless telephones and the centrally located equipment. 
     BACKGROUND OF THE INVENTION 
     The prior art teaches the use of an existing broadband distribution network to carry telephony signals between an existing telephone network and remote transceivers sites in defined cells or sectors. The remote transceivers, sometimes called Remote Antenna Drivers (RADs), are used to establish wireless telephony communication links with wireless telephones operating with an area covered by each RAD. Such broadband distribution networks include, but are not limited to, fiber-optic cable, coaxial cable, and radio links. 
     Between the telephone network and the broadband distribution network is centrally located equipment for carrying the telephony signals between the telephone network and the broadband network. This centrally located equipment typically includes multiple Base Transceiver Stations (BTS) and multiple Remote Antenna Signal Processors (RASPs). Each BTS is connected to the telephone network and to the RASPs. Each RASP is connected to the broadband network. 
     In typical operation, an audio telephony signal from the existing telephone network, and directed to a wireless telephone, is input to a BTS where it is encoded for use in one of the known wireless telephone systems, which include GSM, CDMA and CT2. The encoded telephony signal is used to modulate a radio frequency carrier signal of an intermediate frequency (IF) before being processed further. Before being transmitted to a RASP the IF signal is frequency translated to a higher radio frequency (RF) carrier signal for transmission to a RASP. When the encoded telephony signal, now being carried by the RF carrier signal, is received by the RASP, it is frequency translated back to an IF carrier signal and control signals are added. After this processing the encoded signal and control signals are frequency translated to another RF carrier frequency used for transmission over the broadband distribution network to the Remote Antenna Drivers (RADs) in the cells or sectors. Such transmission over the broadband network is typically over fiber-optic cable or over coaxial cable. 
     Similarly, encoded telephony and control signals received by the RASPs over the broadband distribution network from the Remote Antenna Drivers (RADs) are first converted to an IF carrier signal. The IF carrier signal is initially signal processed in the RASP to remove the control signals, and the IF carrier signal is then translated to an RF signal for transmission to a BTS. In each BTS the RF carrier signal carrying the telephony signal is first converted to an IF carrier signal before the telephony signal is extracted and converted into an analog or digital signal, depending on the type of system, and the encoded telephony signal is then sent to the telephone network. 
     SUMMARY OF THE INVENTION 
     The prior art systems described above utilize much frequency translation of the carrier signal as it passes through the Remote Antenna Signal Processor (RASP) and Base Transceiver Station (BTS). Thus, there is a need in the wireless telephony art for improved, simplified central equipment, such as the RASPs and BTSs, for processing and carrying telephony signals between an existing telephone network and wireless telephones. 
     The above described need in the wireless telephony art is satisfied by the present invention. The improvement comprises simplifying the Base Transceiver Stations (BTS) and the Remote Antenna Signal Processors (RASPs). This simplification lowers the cost of the BTS and RASP equipment, and decreases their complexity, which improves their reliability. 
     This simplification consists of reducing the number of frequency translation steps utilized in the BTS and RASP equipment. More particularly, for telephony signals originating at the telephone network and terminating at a wireless telephone, the IF carrier signal in each BTS is not translated to an RF carrier signal before being transmitted to a RASP. In addition, the IF carrier signal in each RASP is not translated to an RF carrier signal before being transmitted to a BTS. Rather, the frequency of the IF carrier signal in the RASPs and BTSs is the same, and the IF carrier signals are transmitted between the BTSs and the RASPs. This result is a significant savings in the complexity and cost of the RASPs and BTSs. 
     Since each prior art BTS and RASP has a number of telephony signal channels, each of which has the above described RF/IF translations, there is a large reduction in the number of frequency translation stages in this equipment. All IF to RF, and all RF to IF frequency translation stages at the RASP to BTS interface are eliminated. 
    
    
     DESCRIPTION OF THE DRAWING 
     The invention will be better understood upon reading the following Detailed Description in conjunction with the drawing in which: 
     FIG. 1 is a block diagram of a typical wireless telephony system integrated with an exemplary broadband distribution network. 
     FIG. 2 is a block diagram of the reverse direction portion of a prior art Remote Antenna Signal Processor (RASP) used with a wireless telephony system to transmit telephony signals toward Base Transceiver Stations (BTSs); 
     FIG. 3 is a block diagram of the forward direction portion of a prior art Remote Antenna Signal Processor (RASP) used with a wireless telephony system to transmit telephony signals toward Remote Antenna Drivers (RADs); 
     FIG. 4 is a block diagram of the reverse direction portion of a Remote Antenna Signal Processor (RASP) incorporating the teaching of the present invention; 
     FIG. 5 is a block diagram of the forward direction portion of a Remote Antenna Signal Processor (RASP) incorporating the teaching of the present invention; 
     FIG. 6 is a block diagram of a prior art Base Transceiver Station (BTS) used with a wireless telephony system to carry telephony signals between RASPs and BTSs; and 
     FIG. 7 is a block diagram of a Base Transceiver Station (BTS) incorporating the teaching of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the drawing and following detailed description all circuit elements are assigned three digit reference numbers. The first digit of each reference number indicates in which Figure of the drawing an element is shown. The second and third digits of each reference number indicate specific circuit elements. If the same circuit element appears in more than one Figure of the drawing, the second and third digits of the reference number for that circuit element remain the same and only the first digit of the reference number changes to indicate the Figure of the drawing in which the circuit element is located. Thus, signal detector  225  in FIG. 2 is the same signal detector labeled  425  in FIG.  4 . The term “reverse direction” refers to any signals traveling from Broadband Distribution Network  114  toward Telephone System  115 , and the term “forward direction” refers to any signals traveling from Telephone System  115  toward Broadband Network  114  and finally a wireless telephone. In the cable television industry the “forward direction” is referred to as “downstream”, and the “reverse direction” is referred to as “upstream”. This is mentioned because the wireless telephone system described herein can be utilized with a cable television distribution network. As used herein the term “telephony signals” includes voice, data, facsimile and any other type of signals that are sent over a telephone network now or the future. Drawing FIGS. 2 through 5 show prior art and new versions of Remote Antenna Signal Processor (RASP)  117  shown in FIG. 1; and drawing FIGS. 6 and 7 show prior art and new versions of Base Transceiver Station (BTS)  116  shown in FIG.  1 . Throughout this Detailed Description, when FIGS. 2 through 7 are being described, reference is often made to RASP  117  and BTS  116  to remind the reader what circuits these Figures are part of, although the reference numbers  116  or  117  do not actually appear on those Figures. 
     As mentioned in the above Description of the Drawing, FIGS. 2 and 3 respectively show the reverse direction and forward direction portions of a prior art Remote Antenna Signal Processor (RASP)  117 , and FIGS. 4 and 5 respectively show the reverse direction and forward direction portions of a Remote Antenna Signal Processor (RASP)  117  which utilizes the teaching of the present invention. FIG. 6 shows the reverse direction and forward direction portions of a prior art Base Transceiver Station (BTS)  116 , and FIG. 7 shows the reverse direction and forward direction portions of a Base Transceiver Station  116  which utilizes the teaching of the present invention. FIGS. 2 through 7 function in the following manner. 
     In the reverse direction portion of the prior art wireless telephone system described herein, telephony and control signals received from a wireless telephone  119  and a Remote Antenna Driver  118  via Broadband Distribution Network  114  are input to the prior art reverse direction RASP  117  circuitry shown in FIG.  2 . After signal processing to separate telephony signals from control signals, the telephony signals are transmitted from prior art RASP  117  in FIG. 2 to the prior art reverse direction BTS  116  circuitry shown in the upper part of FIG.  6 . After signal processing in BTS  116  to decode the telephony signals, the analog or digital telephony signals are sent to Telephone System  115 . 
     In the forward direction portion of the prior art wireless telephone system described herein, telephony signals are sent from Telephone System  115  to BTS  116  in FIG. 6 to encode the telephony signals before they are transmitted from prior art BTS  116  in FIG. 6 to the prior art forward direction circuitry of RASP  117  shown in FIG.  3 . After adding control signals the combined telephony and control signals are transmitted from the prior art RASP in FIG. 3, via Broadband Distribution Network  114  to a Remote Antenna Driver  118 , and finally to a wireless telephone  119 . 
     Similarly, in the reverse direction portion of a wireless telephone system as described herein, which utilizes the teaching of the present invention, telephony and control signals received from a wireless telephone  119  and a Remote Antenna Driver  118  via Broadband Distribution Network  114 , are input to the reverse direction RASP  117  circuitry shown in FIG.  4 . After separating the control signals the telephony signals are transmitted from RASP  117  in FIG. 4 to reverse direction BTS  116  circuitry shown in the upper part of FIG.  7 . After signal decoding in BTS  116 , the telephony signals are sent to Telephone System  115 . 
     In the forward direction portion of the wireless telephone system as described herein, which utilizes the teaching of the present invention, telephony signals are sent from Telephone System  115  to the forward direction BTS circuitry in the lower portion of FIG. 7 for initial signal encoding before they are transmitted from BTS  116  to the prior art forward direction circuitry of RASP  117  shown in FIG.  5 . After adding control signals, to transmit telephony signals toward telephony and control signals are transmitted from RASP  117  in FIG. 5 to a Remote Antenna Driver  118  and wireless telephone  119  via Broadband Distribution Network  114 . 
     In FIG. 1 is shown a simplified block diagram of an exemplary broadband distribution network  114  integrated with elements of a wireless telephone system. The wireless telephone system includes a plurality of remote transceivers known as Remote Antenna Drivers (RADs)  18   a-f.  There are different types of broadband distribution networks  114  in use, and such networks may utilize coaxial cable, fiber optic cable, microwave links, or combinations of these. The broadband distribution network  114  disclosed herein is a conventional hybrid fiber coaxial (HFC) cable to which a plurality of RADs  118   a-f  are connected. Electrical power is distributed along broadband distribution network  114  to power line amplifiers (not shown) of the broadband distribution network in a manner well known in the art. This electrical power source, or alternate power sources, are also used to provide power to RADs  118   a-f.    
     Integrated with broadband distribution network  114  is a wireless telephony system in which the present invention is utilized. One such wireless telephony system is taught in U.S. patent application Ser. No. 08/695,175, filed Aug. 1, 1996, and entitled “Apparatus And Method For Distributing Wireless Communications Signals To Remote Cellular Antennas”. Another such wireless telephony system is taught in U.S. Pat. No. 5,381,459. The telephony system disclosed herein includes Base Transceiver Stations (BTS)  116   a &amp; b  which are connected to a Telephone System  115 . Base Transceiver Stations  116   a &amp; b  are also connected to Remote Antenna Signal Processors (RASPs)  117   a-d  which are the interface to Broadband Distribution Network  114 . Telephony signals and control signals to be sent between Telephone System  115  and Broadband Distribution Network  114  pass through and are processed by RASPs  117   a-d  and RADs  118   a-f.    
     As is known in the prior art, including the above cited prior patent application and issued patent, one or more frequency bands or channels of the Broadband Distribution Network  114  are reserved to carry telephony signals and control signals between Telephone System  115  and wireless telephones  119 . Telephony signals originating from Telephone System  115  pass through BTSs  116   a &amp; b  and RASPs a-d and are transmitted along with control signals in frequency division multiplexing format, over Broadband Distribution Network  114  to ones of the plurality of RADs  118   a-f,  which are also connected to Broadband Distribution Network  114 , and thence to wireless telephones  119 . Telephony signals originating at wireless telephones  119  are frequency multiplexed together by RADs  118   a-f  and transmitted along with control signals via Broadband Distribution Network  114  to an ones of RASPs  117   a-d,  thence to Base Transceiver Stations  116   a &amp; b,  and finally to Telephone System  115 . 
     In each of BTSs  116   a &amp; b  there are a plurality of transceiver modules (not shown), as is known in the wireless telephony art, each of which operates at a single frequency, and which can handle a predetermined maximum number of telephony calls from wireless telephones. In the wireless telephone system described and claimed herein, the frequency at which the RADs  118   a-f  are assigned to operate must correspond to the operating frequency of an assigned BTS  116   a  or  b  transceiver module. If a particular RAD  118  is re-assigned to function with a different transceiver module within BTS  116   a  or  b,  circuit settings within the particular RAD  118  must also be changed to function with the different transceiver module. In the wireless telephony art, transceiver modules in a BTS  116  are also referred to as channel card modules and radio modules. 
     In FIG. 1 are shown three rows of RADs  118 . Typically, a number of RADs  118   a-f  are spaced along, and connected to, Broadband Distribution Network  114  to provide overlapping signal transmission and reception coverage for the entire wireless telephone system. Some of the RADs  118   a-f  are physically located near the boundary between two or more cells or sectors and, depending on the frequency of operation they are set to, can be used to handle wireless telephony traffic in one or more of the sectors or cells. In FIG. 1, RADs  118   e &amp; f  in the bottom row are physically located along Broadband Distribution Network  114  and are configured to handle wireless telephony traffic in a first sector. RADs  118   c &amp; d  in the middle row in FIG. 1 are configured and located to handle wireless telephone traffic in a second, adjacent sector. Finally, RADs  118   a &amp; b  are configured and located to handle wireless telephone traffic in a third, adjacent sector. 
     Each of RADs  118   a-f  has antennas  120 ,  121 ,  122  which are used to transmit to, and receive signals from, remote wireless telephones  119 . Antenna  120  is used to transmit telephony signals to wireless telephones  119 , while antennas  121  and  122  are used to receive telephony signals from wireless telephones  119 . Antenna  121  is called the primary antenna, and antenna  122  is called the diversity antenna. Antennas  121  and  122  are physically spaced and cooperate to minimize signal fading and thereby provide continuous signal reception from wireless telephones  119 . 
     In FIG. 2 is shown a block diagram of the reverse direction portion of a prior art Remote Antenna Signal Processor (RASP)  117 . The reverse direction circuitry processes telephony and control signals received from wireless telephones and RADs  118 , and received via a Broadband Distribution Network  114 , and forwards them to prior art Base Transceiver Station  116  shown in FIG.  6 . 
     Within the prior art RASP circuit are three parallel channel circuits  211   a,    211   b  and  211   c.  These three circuits are referred to as alpha, beta and gamma channels and they operate in the same manner except for their frequency of operation to handle telephony signals in different channels. To simplify the description of the reverse direction RASP circuit shown in FIG. 2, only alpha channel circuit  211   a  is described in detail. There may be more than three such channel circuits in a RASP  117 . 
     Telephony signals from a wireless telephone  119 , and control signals from a RAD  118  that is carrying the telephony signals, are carried over Broadband Distribution Network  114  to bandpass filter  223  at the input of alpha channel  211   a.  These telephony and control signals are divided for further processing as described further in this detailed description. Filter  223  removes out of band signals that are present on Broadband Distribution Network  114  before the telephony and control signals are input to signal divider  224 . Divider  224  divides and applies the combined telephony and control signals to both divider  226  and to signal detector  225 . 
     Signal detector  225  separates the control signals from the telephony signal and forwards them to a microprocessor for processing. The microprocessor analyzes the control signals and causes circuit adjustments to be made in RASPs  117  and RADs  118 . 
     Divider  224  also applies the telephony signal to divider  226  which again divides the signal, which includes the combined signals from primary receive antenna  121  and diversity receive antenna  122 , and applies them to mixers  227   a  and  227   b.  As briefly described hereinabove, the telephony signal received by the primary receive antenna  121  and diversity receive antenna  122  from a single RAD  118  are frequency multiplexed together. Mixers  227   a  and  227   b  are used to separate these two frequency multiplexed telephony signals. 
     Mixer  227   a  has a second input from oscillator OSC 1 , and mixer  227   b  has a second input from oscillator OSC 2 . The frequency of oscillators OSC 1  and OSC 2  is different and the mixing process of mixers  227   a  and  227   b  causes the modulated carrier signal output from each of them to have the same intermediate frequency (IF) carrier signal. The frequency of oscillators OSC 1  and OSC 2  are controlled by the microprocessor and are set according to the assigned frequency of operation for the alpha channel on Broadband Distribution Network  114 . 
     The heterodyning process of mixers  227   a  and  227   b  produce a number of unwanted signals which are removed respectively by bandpass filters  229   a  and  229   b,  and which respectively pass only the desired telephony signal from the primary antenna and the diversity antenna of a RAD  118 . 
     Only the primary receive antenna telephony signal is output from filter  229   a  and is input to mixer  230   a  where it is mixed with a signal from oscillator OSC 3 . The heterodyning process of mixer  230   a  is used to translate the intermediate frequency carrier signal, modulated with the primary receive antenna telephony signal, to a radio frequency (RF) carrier signal that is transmitted via path alpha  1  to prior art Base Transceiver Station  116  in FIG.  6 . The heterodyning process of mixer  230   a  also produces a number of unwanted signals that are removed by bandpass filter  231   a.    
     Only the secondary receive antenna telephony signal is output from filter  229   b  and is input to mixer  230   b  where it is mixed with a signal from oscillator OSC 4 . The heterodyning process of mixer  230   b  is used to translate the IF carrier signal, modulated with the secondary receive antenna telephony signal, to an RF carrier signal that is transmitted via path alpha  2  to prior art Base Transceiver Station  116  in FIG.  6 . The heterodyning process of mixer  230   b  also produces a number of unwanted signals that are removed by bandpass filter  231   b.    
     The alpha, beta and gamma channels  211   a,    211   b  and  211   c  operate in the same manner except for their frequency of operation. To simplify the description of RASP  117  circuitry only the alpha channel circuitry  211   a  is described in detail above, and is not repeated for beta channel  211   b  and gamma channel  211   c.    
     In FIG. 3 is shown a block diagram of the forward direction portion of a prior art Remote Antenna Signal Processor (RASP)  117 . The forward direction circuitry processes telephony signals received from a Base Transceiver Station  116  to add control signals, and transmits them via Broadband Distribution Network  114  to and RADs  118  to wireless telephones  119  in FIG.  1 . Within the prior art RASP  117  are three parallel forward direction circuits which also are referred to as alpha, beta and gamma channels  334   a,    334   b  and  334   c.  They all operate in the same manner except for their frequency of operation, so only the operation of the alpha channel  334   a  is described in detail. 
     Telephony signals modulating an RF carrier signal are received from prior art BTS  116  (FIG. 6) in the alpha channel are input to bandpass filter  332  to remove all out of band signals. The filtered RF signals are then input to mixer  333  along with a signal from oscillator OSC 5  for frequency translation to an IF carrier frequency. The heterodyning process of mixer  333  also produces a number of unwanted signals which are removed by bandpass filter  335 . This IF carrier signal is later translated back to an RF carrier signal before being transmitted over Broadband Distribution Network  114  to Remote Antenna Driver  118  for transmission to wireless telephones  119  in a manner known in the prior art. 
     The filtered IF carrier signal, modulated by the telephony signal, is input to a second mixer  336  along with an input from oscillator OSC 6 . The frequency of oscillator OSC 6 , and corresponding oscillators in the beta and gamma channels  334   b  and  334   c  are set by a microprocessor. The result is that the IF carrier signal in the alpha, beta and gamma channels is different. 
     The IF carrier signal output from mixer  336  is input to combiner  338  along with the IF carrier signals from beta channel  334   b  and gamma channel  334   c.  Combiner  338  combines the three IF carrier signals, each at a different frequency, into a single frequency multiplexed signal which is input to bandpass filter  339  where all unwanted frequencies from the heterodyning process of mixer  336 , and the similar mixers in the beta and gamma channels, are removed. Only the three frequency multiplexed IF carrier signals, modulated respectively by the alpha, beta and gamma channel telephony signals, are passed through filter  339  to mixer  340 . 
     Mixer  340  is used to translate the frequency of the IF carrier signals output from filter  339 , now carrying telephony signals from the alpha  334   a,  beta  334   b  and gamma  334   c  channels, to an RF carrier signal for transmission over Broadband Distribution Network  114  to a RAD  118 . 
     The output of mixer  340  includes many unwanted signals which are removed by bandpass filter  343 . The desired RF carrier signal is amplified by amplifier  344  before being input to diplexer  345  along with a second input that is now described. 
     On lead “f” from BTS  116  is a reference signal. This reference signal is used to control reference oscillator  346  to transmit a reference oscillator signal to all RADs  118  to accurately set the frequency of operation of their internal oscillators (not shown). 
     Diplexer  445  is used to combine the RF carrier signal described above with the reference oscillator  346  signal for transmission over Broadband Distribution Network  114  to RADs  118 . 
     In the preceding description of a prior art Remote Antenna Signal Processor (RASP)  117  it can be appreciated that the carrier signals carrying telephony and control signals are frequency translated up and down, to provide an IF carrier signal inside RASP  117  but an RF carrier signal outside of RASP  117 . The same thing is done in prior art Base Transceiver Stations  116  as described further in this detailed description. These multiple steps of frequency translation introduce noise and signal distortions, as well as higher cost, into the cost of a wireless telephone system. 
     In FIG. 4 is shown a circuit block diagram of the reverse direction portion of a Remote Antenna Signal Processor (RASP)  117  incorporating the teaching of the present invention. When comparing the new reverse direction RASP  117  circuitry shown in FIG. 4 with the prior art reverse direction RASP  117  circuitry shown in FIG. 2, it can be seen that the two circuits are similar but the new reverse direction circuitry shown in FIG. 4 is much simpler. Those portions of the alpha, beta, and gamma channel circuits in FIG. 4 that have corresponding circuits in FIG. 2 operate in the same manner and for the same purposes as the corresponding circuits. Thus, for example, divider  226  in FIG. 2 performs the same function and for the same purpose as divider  426  in FIG.  4 . Accordingly, the operation of the corresponding individual circuit elements in alpha channel  411   a  in FIG. 4 are not described herein, and the reader is referred to the circuit description for FIG.  2 . 
     In alpha channel  411   a  it can be seen that there are no mixers and filters corresponding to mixers  230   a &amp; b  and filters  231   a &amp; b  in FIG.  2 . These last mentioned mixers and filters in the prior art reverse direction RASP  117  circuitry are used to translate the frequency of the reverse direction IF carrier signal used in the reverse direction alpha channel  211   a  circuit to an RF carrier signal for transmitting the telephony signals to Base Transceiver Station  116  in FIG.  6 . As mentioned previously, in accordance with the teaching of the present invention, the IF carrier signal is used to carry encoded telephony signals between RASPs  117  and BTSs  116 , so circuitry in RASP  117  to translate the intermediate frequency carrier signal to an RF carrier signal is not needed. In reverse direction alpha channel  411   a  there is a reduction in complexity of four circuits as described immediately above. Between alpha channel  411   a,  beta channel  411   b,  and gamma channel  411   c  a total of twelve circuits are eliminated in just the reverse direction circuits. The cost savings in one RASP  117  is obvious, and the cost savings are increased when it is considered that there are many RASPs  117 . 
     Turning now to FIG. 5, therein is shown a block diagram of the forward direction portion of a Remote Antenna Signal Processor (RASP)  117  incorporating the teaching of the present invention. When comparing the new forward direction RASP  117  circuitry shown in FIG. 5 with the prior art forward direction RASP  117  circuitry shown in FIG. 3 it can be seen that the two circuits are similar but the new forward direction circuitry shown in FIG. 5 is much simpler. Those circuits in the alpha, beta, and gamma channels  534   a,    534   b  and  534   c  in FIG. 5 that have corresponding circuits in FIG. 3 operate in the same manner and for the same purposes as the corresponding circuits in FIG.  3 . Thus, for example, combiner  338  in FIG. 3 performs the same function and for the same purpose as combiner  538  in FIG.  5 . Accordingly, the operation of the corresponding individual circuit elements in alpha channel  534   a  in FIG. 5 are not described herein, and the reader is referred to the circuit description for FIG.  3 . 
     In alpha channel  534   a  of FIG. 5 it can be seen that there is no filter and mixer corresponding to filter  332  and mixer  333  in FIG.  2 . Mixer  333  and filter  332  in the prior art forward direction RASP  117  circuitry are used to translate the forward direction RF carrier signal received from Base Transceiver Station  116  (FIG. 6) to an IF carrier signal. This also applies to forward direction beta channel  534   b,  and gamma channel  534   c.    
     In new forward direction alpha channel  534   a  there is a reduction in complexity of two circuits as described in the previous paragraph. Between alpha channel  534   a,  beta channel  534   b,  and gamma channel  534   c  a total of six circuits are eliminated in the forward direction RASP circuits. The cost savings in one RASP  117  is obvious, and the cost savings are increased when it is considered that there are many RASPs  117 . 
     In summary, between the reverse direction and forward direction circuits of new RASP  117  there is a reduction of  18  circuits when compared to prior art RASPs. The savings are obviously significant. In addition to cost savings, a simpler RASP  117  will have fewer maintenance problems which results in additional savings. Further savings are achieved by lower power consumption of each RASP  117 . 
     In FIG. 6 is shown a block diagram of a prior art Base Transceiver Station (BTS)  116  used with a wireless telephony system. Each BTS  116  has three reverse direction circuits designated alpha, beta, and gamma; and three forward direction circuits designated alpha, beta, and gamma. In FIG. 6 only one reverse direction circuit and one forward direction circuit are shown for the purpose of simplicity. The three reverse direction circuits are all identical and the three forward direction circuits are all identical, so there is no need to show and describe the reverse direction and forward direction beta and gamma circuits to understand their operation. 
     As described above with reference to FIG. 2, Remote Antenna Signal Processor (RASP)  117  uses an RF carrier signal to transmit reverse direction telephony signals to the reverse direction circuitry of Base Transceiver Station (BTS)  116  via Broadband Distribution Network  114 . In FIG. 6 the prior art reverse direction circuitry is at the top of the Figure. The RF carrier signal received from a prior art RASP  117  in the alpha channel, modulated by an encoded telephony signal, is input to filter  647  which removes spurious signals at the input of BTS  116 . The received signal is then amplified by amplifier  648  and input to transceiver  649 . Transceiver  649  is used to translate the received RF carrier signal to an IF carrier signal which is input to demodulator  650 . Demodulator  650  extracts the encoded, analog telephony signal from the IF carrier signal in a manner well-known in the art. In the wireless telephony system described herein the carrier signal is phase shift key modulated. Upon demodulation in demodulator  650  the analog, encoded telephony signal is extracted. The demodulated analog, encoded, telephony signal is then input to analog to digital converter  651  which digitizes the encoded analog telephony signal. The now digitized and encoded telephony signal is then input to decoder  652  which decodes the signal to obtain the digitized telephony signal which is sent to Telephone System  115 . The type of decoding that is done depends upon the system, and the types include, but are not limited to, the well-known CDMA and GSM systems. 
     The forward direction side of prior art BTS  116  is in the bottom row of FIG.  6 . Digitized telephony signals received from Telephone System  115  are input to encoder  653 . The type of encoding that is done depends upon the type of system and includes, but is not limited to, the well-known CDMA and GSM systems. The encoded digital telephony signal is then input to digital to analog converter  654  which converts the telephony signal into an analog signal. The now analog, encoded telephony signal is then input to modulator  655  which, in the prior art Base Transceiver Station (BTS)  116  shown in FIG. 6, phase shift key modulates an IF carrier signal in a matter well-known in the art. The IF carrier signal, modulated by the analog, encoded telephony signal, is then input to transceiver  666  which translates the IF carrier signal frequency to an RF carrier signal. The modulated RF carrier signal is then amplified by amplifier  667 , spurious signals are filtered out by filter  668  and the RF carrier signal is sent to RASP  117  in FIG.  3 . RASP  117  receives the RF carrier signal and processes it in the manner previously described with reference to FIG.  3 . 
     In FIG. 7 is shown a block diagram of a new Base Transceiver Station (BTS)  116  which utilizes the teaching of the present invention. Each BTS  116  has three reverse direction circuits designated alpha, beta, and gamma; and three forward direction circuits designated alpha, beta, and gamma. In FIG. 7 only one reverse direction circuit and one forward direction circuit are shown. The three reverse direction circuits are identical and the three forward direction circuits are identical, so there is no need to show and describe the reverse direction and forward direction beta and gamma circuits to understand their operation. The reader is referred to the circuit description for FIG.  6 . 
     When comparing the new reverse direction and forward direction BTS  116  circuitry shown in FIG. 7 with the prior art reverse direction and forward direction BTS  116  circuitry shown in FIG. 6, it can be seen that the two circuits are similar but the new reverse direction and forward direction circuitry shown in FIG. 7 is much simpler. Those portions of the alpha, beta, and gamma channel circuits in FIG. 7 that have corresponding circuits in FIG. 6 operate in the same manner and for the same purposes as the corresponding circuits in FIG.  6 . Thus, for example, A/D converter  651  in FIG. 6 performs the same function and for the same purpose as A/D converter  751  in FIG.  7 . Also, encoder  653  in FIG. 6 performs the same function and for the same purpose as encoder  753  in FIG.  7 . Accordingly, the operation of the individual circuit elements in the reverse direction and forward direction circuits in FIGS. 7 are not described herein, and the reader is referred to the circuit description for FIG. 6 for an understanding of the operation of the circuit elements  750 ,  751 ,  752 ,  753 ,  754 , and  755  in FIG.  7 . 
     When comparing the prior art BTS in FIG.  6  and the new BTS in FIG. 7, it should noted that filters  647  and  668 , amplifiers  648  and  667 , and transceivers  649  and  666  are missing in FIG.  7 . These circuit elements are not needed in the modified wireless telephone system per the teaching of the present invention. Filter  647 , amplifier  648 , and transceiver  649  in the reverse direction portion of BTS  116  serve the primary function of translating the RF carrier signal received from a prior art RASP  117  to an IF carrier signal. Transceiver  666 , amplifier  667  and filter  668  in the forward direction portion of BTS  116  serve to translate the IF carrier signal used inside each BTS to an RF carrier signal for transmission to a RASP  117 . As mentioned previously, in accordance with the teaching of the present invention the IF carrier signal is used to carry the telephony signals between RASPs  117  and BTSs  116 , so circuits in prior art BTS  116  used to translate the IF carrier signal to an RF carrier signal for transmission to a RASP  117  are not needed. Three circuits are thereby eliminated. 
     Similarly, as described hereinabove with reference to FIG. 5, the new forward direction RASP  117  circuitry is designed to receive an IF carrier signal from BTS  116  per the teaching of the present invention. The primary purpose of transceiver  666 , amplifier  667 , and filter  668  in prior art BTS  116  is to translate the IF carrier signal used within BTS  116  to a RF carrier signal for transmission to a RASP  117 . Thus, there is no need to translate the IF carrier signal within RASP  117  to an RF carrier signal, so circuits  666 ,  667  and  668  are eliminated. 
     It can be understood that each channel in Base Transceiver Station (BTS)  116  requires six less circuits when the teaching of present invention is implemented. With there being alpha, beta and gamma channels in the BTS  116  of FIG. 7, as described hereinabove, a total of eighteen circuits are eliminated in one BTS  116 . In a typical wireless telephony system there are a number of Base Transceiver Stations (BTS)  116  so the cost savings is very significant. In addition to cost savings, a simpler BTS  116  will have fewer maintenance problems which results in additional savings. Further savings are achieved by lower power consumption of each BTS  116 . 
     While the Base Transceiver Station (BTS)  116  described hereinabove is an analog version and utilizes analog to digital converter  651  and digital to analog converter  654 , all digital BTSs exist. In an all digital BTS  116 , converters  651  and  654  are deleted. 
     While what has been described hereinabove is the preferred embodiment of the present invention, it may be appreciated that one skilled in the art may make numerous changes without departing from the spirit and scope of the present invention. For example, demodulator  750  and modulator  755  of new BTS  116  in FIG. 7 may be located instead in RASP  117 .