Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-03-29
2002-06-18
Trost, William (Department: 2746)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S424000, C342S352000, C342S357490, C342S357490
Reexamination Certificate
active
06408178
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to wireless communications systems and methods, and more particularly to wireless mobile terminals, systems and methods.
BACKGROUND OF THE INVENTION
Public wireless radiotelephone systems are commonly employed to provide voice and data communications to subscribers. For example, analog cellular radiotelephone systems, such as designated AMPS, ETACS, NMT-450, and NMT-900, have long been deployed successfully throughout the world. Digital cellular radiotelephone systems such as those conforming to the North American standard IS-54 and the European standard GSM have been in service since the early 1990's. More recently, a wide variety of wireless digital services broadly labeled as PCS (Personal Communications Services) have been introduced, including advanced digital cellular systems conforming to standards such as IS-136 and IS-95, lower-power systems such as DECT (Digital Enhanced Cordless Telephone) and data communications services such as CDPD (Cellular Digital Packet Data). These and other systems are described in
The Mobile Communications Handbook
, edited by Gibson and published by CRC Press (1996).
FIG. 1
illustrates a conventional terrestrial wireless communication system
20
that may implement any one of the aforementioned wireless communications standards. The wireless system may include one or more wireless mobile terminals
22
that communicate with a plurality of cells
24
served by base stations
26
and a Mobile Telephone Switching Office (MTSO)
28
. Although only three cells
24
are shown in
FIG. 1
, a typical cellular radiotelephone network may comprise hundreds of cells, may include more than one MTSO
28
and may serve thousands of wireless mobile terminals
22
.
The cells
24
generally serve as nodes in the communication system
20
, from which links are established between wireless mobile terminals
22
and an MTSO
28
, by way of the base stations
26
servicing the cells
24
. Each cell
24
will have allocated to it one or more dedicated control channels and one or more traffic channels. The control channel is a dedicated channel used for transmitting cell identification and paging information. The traffic channels carry the voice and data information. Through the communication system
20
, a duplex radio communication link
30
may be effected between two wireless mobile terminals
22
or between a wireless mobile terminal
22
and a landline telephone user
32
via a Public Switched Telephone Network (PSTN)
34
. The base station
26
generally handles the radio communications between the base station
26
and the wireless mobile terminal
22
. In this capacity, the base station
26
may function as a relay station for data and voice signals.
FIG. 2
illustrates a conventional celestial (satellite) communication system
120
. The satellite wireless communication system
120
may be employed to perform similar functions to those performed by the conventional terrestrial wireless communication system
20
of FIG.
1
. In particular, the celestial wireless communication system
120
typically includes one or more satellites
126
that serve as relays or transponders between one or more earth stations
127
and satellite wireless mobile terminals
122
. The satellite
126
communicates with the satellite wireless mobile terminals
122
and earth stations
127
via duplex communication links
130
. Each earth station
127
may in turn be connected to a PSTN
132
, allowing communications between the wireless mobile terminals
122
, and communications between the wireless mobile terminals
122
and conventional terrestrial wireless mobile terminals
22
(
FIG. 1
) or landline telephones
32
(FIG.
1
).
The satellite wireless communication system
120
may utilize a single antenna beam covering the entire area served by the system, or as shown in
FIG. 2
, the satellite wireless communication system
120
may be designed such that it produces multiple, minimally-overlapping beams
134
, each serving a distinct geographical coverage area
136
within the system's service region. A satellite
126
and coverage area
136
may serve a function similar to that of a base station
26
and cell
24
, respectively, of the terrestrial wireless communication system
20
.
Thus, the satellite wireless communication system
120
may be employed to perform similar functions to those performed by conventional terrestrial wireless communication systems. In particular, a satellite radiotelephone communication system
120
may have particular application in areas where the population is sparsely distributed over a large geographic area or where rugged topography tends to make conventional landline telephone or terrestrial wireless infrastructure technically or economically impractical.
As the wireless communication industry continues to advance, other technologies will most likely be integrated within these communication systems in order to provide value-added services. One such technology being considered is a Global Positioning System (GPS). Therefore, it would be desirable to have a wireless mobile terminal with a GPS receiver integrated therein. It will be understood that the terms “global positioning system” or “GPS” are used to identify any spaced-based system that measures positions on earth, including the GLONASS satellite navigation system.
A GPS system
300
is illustrated in FIG.
3
. As is well known to those having skill in the art, “GPS” refers to a space-based trilateration system using satellites
302
and computers
308
to measure positions anywhere on the earth. The term GPS was originally introduced and often is used to refer to a system developed by the United States Department of Defense as a navigational system. However, for purposes of this application, the term GPS refers more generally to both the Department of Defense system and other space-based systems such as GLONASS. Compared to other land-based systems, GPS may be unlimited in its coverage, may provide continuous 24-hour coverage regardless of weather conditions, and may be highly accurate. While the GPS technology that provides the greatest level of accuracy has been retained by the government for military use, a less accurate Standard Positioning Service (SPS) has been made available for civilian use.
In operation, a constellation of 24 GPS satellites
302
orbiting the earth continually emit a GPS radio frequency signal
304
at a predetermined chip frequency. A GPS receiver
306
, e.g., a hand-held radio receiver with a GPS processor, receives the radio signals from visible satellites and measures the time that the radio signals take to travel from the GPS satellites to the GPS receiver antenna. By multiplying the travel time by the speed of light, the GPS receiver can calculate a range for each satellite in view. From additional information provided in the radio signal from the satellites, including the satellite's orbit and velocity and correlation to its onboard clock, the GPS processor can calculate the position of the GPS receiver through a process of trilateration.
More particularly, the GPS signal
304
generally consists of a spread-spectrum signal that has a code-length of 1023 chips (bits), and it is transmitted at a chip-rate of 1.023 MHz. This results in a code period of one millisecond. Overlaid on top of the spread-spectrum sequence is a 50 bits/second (bps) navigation message which, typically, contains ephemeris/almanac data as well as timing information which is used to timestamp the transmit time of the signal from the GPS satellite
302
. The timestamp, which is generally transmitted in each sub-frame of the 1500 bit navigation message, each sub-frame consisting of 300 bits, is used to calculate the integer number of C/A (coarse acquisition Gold code) code lengths between the GPS satellite
302
and current position of GPS receiver
306
.
Because of the slow transmission rate (50 bps) of the navigation message, it typically takes at least 6 seconds to decode a sub-frame of the navigation
Jolley Edward V.
Solve Torbjorn
Wickstrom Daniel
Tran Congvan
Trost William
LandOfFree
Systems and methods for resolving GPS pseudo-range ambiguity does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Systems and methods for resolving GPS pseudo-range ambiguity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Systems and methods for resolving GPS pseudo-range ambiguity will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2958156