Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1999-11-08
2004-09-14
Gelin, Jean (Department: 2681)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S082000
Reexamination Certificate
active
06792289
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to communications. More particularly, the invention concerns a non-bandlimiting method and apparatus for sharing common antennas used to receive and transmit signals in a wireless communications network.
2. Description of the Background Art
A modern day communication network is required to support a variety of applications. One such communication network is a code division multiple access (CDMA) network that conforms to the “TIA/EIA/IS-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,” hereinafter referred to as IS-95. The CDMA network allows for wireless voice and data communications between users. The use of CDMA techniques in a multiple access communication networks is disclosed in U.S. Pat. No. 4,901,307, entitled “SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,” issued Feb. 13, 1990 and U.S. Pat. No. 5,103,459, entitled “SYSTEM AND METHOD FOR GENERATING WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM,” issued Apr. 7, 1992, both of which are assigned to the assignee of the present invention and incorporated by reference herein.
In a CDMA network, a land-based data network can communicate with a subscriber station, typically a mobile cellular telephone, via one or more base stations. The base stations are communicatively coupled to the subscriber stations by a “forward link.” The subscriber station communicates with the land-based data network by transmitting data on a “reverse link” to a base station. A link is simply a communications connection used to transmit data from a source to a destination. The base station receives and routes received data, using a base station controller (BSC), to the land-based data network. For example, a subscriber station transmits a signal to the base station using an antenna and another antenna located at the base station receives the transmitted signal. This signal is processed and communicated further using the land-based data network. In a wireless network, a forward link and a reverse link may or, may not be allocated separate frequencies. Given the growing demand for wireless data applications, the need for very efficient wireless data communication networks have become increasingly significant.
To allow a network to handle more subscriber calls, the geographical area served by the communications network may be split up. These partitioned areas are called sectors or “cells,” and one or more base stations may be assigned to service the communications from subscriber stations located within any sector or sectors. Further, a signal received at an antenna may be routed to one or more base stations. As mentioned above, a base station (BTS) both receives and transmits communication signals. It is common for a BTS to have a single transmit signal and two receive signals, and to allow BTS transceiver subsystems from two different sectors to share an antenna.
To share antennas, a receive multi-coupler (RMC)
100
as shown in
FIG. 1
is commonly used. Antenna
102
receives and transmits signals from the BTS to which the antenna
102
is connected. A surge protector
104
may be coupled to the antenna to prevent against unusual energy conditions, such as lighting striking the antenna. A duplexer
106
is coupled to the antenna
102
to facilitate the simultaneous transmission of signal
114
and the receipt of signals
116
and
118
. Signal
114
is transmitted using antenna
102
, and signals
116
and
118
are received using the antenna
102
. A low noise amplifier (LNA)
108
, a gain adjustment attenuator
110
, and a power divider
112
are arranged to provide the signals
116
and
118
. LNA
108
may also be connected to a fault detection unit
120
. The design shown in
FIG. 1
requires special filters, also referred to as duplexer
106
, to split or combine signals using varying frequencies. Each of the signals
114
,
116
, and
118
are communicated to the base station using separate ports (not shown).
FIG. 1
also shows a second arrangement within RMC
100
that works substantially as described above.
It is also common practice for a BTS to combine one transmit signal and one receive signal into one port rather than the multi-port configuration shown in FIG.
1
. However, in this case, the RMC
100
as shown will not work. Another duplexer such as duplexer
106
would have to be added at the transmit/receive (TX/RX) inputs to separate a transmit signal from a received signal, and then use distinctly different and separate paths to route the signals. A path is a route between any two nodes, and may include more than one branch. This design separates the direction of the TX/RX signals, but does not consider the frequencies of the signals. Further, this modification to RMC
100
increases its cost and size, and reduces the performance of the unit.
What is needed is an invention that provides a method and apparatus that allows TX/RX signals to be processed using common hardware elements and substantially similar paths. The invention should allow a TX signal and a RX signal to be communicated to a base station using a common port, and provide for a received signal to be split and routed to a different base station using the same hardware.
SUMMARY OF THE INVENTION
The present invention is a method and apparatus that processes combined TX/RX signals using common hardware elements. The invention permits one port to commonly communicate a TX signal and a RX signal using a single port to a base station.
In one embodiment, the present invention comprises a non-band limiting method to share antennas where a signal to be transmitted is received at a first port. This first port is communicatively coupled to a base station. This “transmit” signal travels from the first port through a plurality of direction units prior to being transmitted by an antenna. The direction units assure the transmit signal follows a desired path through the sub-network. Another signal is received at a second port communicatively coupled to an antenna. This “received” signal conceptually travels in a reverse direction to the transmit signal and through at least one of the direction units. The received signal shares a somewhat common path with the transmit signal, and is admitted to the base station at the same port that the transmit signal was received. The received signal is also split and received by a second base station.
In another embodiment, the invention may be implemented to provide an apparatus for sharing antennas that is non-band limiting. A transmit signal is received at a first port coupled to a base station. The transmit signal travels from the first port through a plurality of circulators prior to being transmitted by an antenna. A received signal is received at a second port communicatively coupled to the antenna. The received signal conceptually travels through the apparatus in a reverse direction to the transmit signal, through at least one of the circulator units, and is admitted to the transmitting base station using the same port from which the transmit signal originated. The received signal may also be split and received by a second base station.
The invention affords its users with a number of distinct advantages as found in its various embodiments. For example, one advantage is that the invention may be used in most wireless telecommunication networks where antenna sharing is desirable. Another advantage is that the direction, or path, of the transmit signal and the received signal are controlled, not the frequency of the signals. Still another advantage is that both the transmit signal and the received signal are processed using common hardware elements.
REFERENCES:
patent: 4041389 (1977-08-01), Oades
patent: 4109202 (1978-08-01), Kudsia et al.
patent: 4186344 (1980-01-01), Higuchi et al.
patent: 4206464 (1980-06-01), Hirsch
patent: 4430619 (1984-02-01), Epsom et al.
patent: 4791421 (1988-12-01), Morse et al.
patent: 4901307 (1990-02-01), Gilhousen et al.
p
Edwards Christopher O.
Gelin Jean
Miller Russell B.
Qualcomm Incorporated
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