Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-06-10
2003-01-07
Trost, William (Department: 2683)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S552100, C455S458000
Reexamination Certificate
active
06505042
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to communication systems, and more particularly, to a system and method for establishing a communication link between a wireless telephone and a base station transceiver subsystem (BTS).
BACKGROUND OF THE INVENTION
Wireless communication devices, such as cellular telephones, rely on a network of cell sites located throughout a geographical-region to receive and transmit information. As shown in
FIG. 1
, a cellular telephone
10
is in communication with multiple cell sites
16
whenever the cellular telephone
10
is. powered on. Each cell site
16
includes a base station transceiver subsystem (BTS)
20
transmitting information to and receiving information from the cellular telephone
10
by using a cell site antenna
24
. Multiple cell sites are strategically located throughout a geographical region so that cellular telephone coverage is consistent and continuous throughout the region. Groups of the cell sites
16
are connected to a base station controller (BSC)
30
a,
30
b
by land lines
32
such that the cell sites
16
connected to the BSCs
30
a,
30
b
will receive and transmit the same information. Although only two BSCs
30
a,
30
b
are shown in
FIG. 1
, as many as 30 to 40 BSCs may be necessary to connect a sufficient number of the cell sites
16
together to provide adequate telephone coverage throughout a metropolitan region.
Upon powering up the cellular telephone
10
, it transmits a number of operational parameters to one of the BSCs
30
a,
30
b
to establish a communication link. The transmission from the cellular telephone
10
is received by one of the cell sites
16
in the vicinity, and the operational parameters are communicated via the associated BTS
20
to the BSCs
30
a,
30
b
to which the particular cell site
16
and BTS
20
are connected. The BSCs
30
a,
30
b
use the operational parameters to identify and register the cellular telephone
10
within its area of coverage. When the cellular telephone
10
is not currently being used to transmit or receive calls, the cellular telephone
10
remains in an idle state until there is a need to establish a communication link between the cellular telephone
10
and one of the BTSs
20
.
The cellular telephone
10
and the cell sites
16
in the vicinity, use a frequency pair, known as a control channel
25
for signaling and exchanging operational parameters among them. Each cell site
16
contains a dedicated forward and reverse control channel. The reverse control channel is also called an access channel
27
. Prior to receiving and transmitting information, as in a cellular call, a communication link between the cellular telephone
10
and one of the several cell sites
16
or BTSs
20
in the surrounding region must be established. Establishing such a communication link is facilitated by use of the control channel
25
and the access channel
27
on which the cellular phone
10
or the BTS
20
may exchange short messages. There is a paired control channel
25
and access channel
27
for each of the BTSs
20
within range of the cellular telephone
10
. The information transmitted by the BTS
20
to the cellular phone
10
on the control channel
25
and by the cellular phone
10
to the BTS
20
on the access channel
27
provide the BTSs
20
with the necessary information to establish a communication link.
However, in the event the communication link fails to be established between the cellular telephone
10
and one of the BTSs
20
, the incoming call will not be established, but will be aborted. Therefore, it can be appreciated that there is a need for a cellular telephone that increases the probability that a communication link will be established between the cellular phone and a BTS. The present invention provides this and other advantages, as will be apparent from the following detailed description and accompanying figures.
SUMMARY OF THE INVENTION
The present invention is embodied in a system and method directed to increase the likelihood that a communication link between a user station and a BTS is established, when an incoming message is to be received by the user station. In one embodiment, after receiving a paging message or incoming call, the system includes a user station that transmits a response message for a timeout period to a cell site or BTS, from which the user station received the paging message having the strongest signal strength, that is, to the primary BTS. In the event the primary BTS does not transmit an acknowledgment message to the user station before the timeout period expires, the user station then transmits the response message to that BTS from which the user station received the paging message having the second strongest signal strength on the respective control channel.
A BSC transmits the paging message to reach a cellular phone through sending simultaneous pages in multiple control channels (or paging channels) assigned to the BTSs. This invention will allow the cellular phone to establish communication with a second BTS, by using the control channel on which the paging message having the second strongest signal strength is received, when it fails the first time.
The user station includes a receiver to receive the paging message transmitted by multiple BTSs. The user station further includes a processor that analyzes and prioritizes the multiple BTSs into a sequence based upon the strength of the paging messages received. Coupled to the processor is a timer for timing the timeout period. The user station also includes a transmitter for transmitting the response message to one of the multiple BTSs in response to receiving the paging message.
In another embodiment of the present invention, the user station not only transmits the response message to the BTSs from which the user station receives the paging messages having the first and second strongest signals but will also transmit the response message to the BTS from which the user station receives the paging message having the next strongest signal when the timeout period has expired. The cellular telephone will continue transmitting the response message to each succeeding BTS in the sequence until the BTS to which the cellular telephone is currently transmitting responds with an acknowledgment message, or the number of BTSs to which the cellular phone may transmit is exhausted.
REFERENCES:
patent: 4481670 (1984-11-01), Freeburg
patent: 5199031 (1993-03-01), Dahlin
patent: 5511069 (1996-04-01), England et al.
patent: 6073021 (2000-06-01), Kumar et al.
patent: 6064886 (2000-08-01), Forez et al.
patent: 6112082 (2000-08-01), Almgren et al.
patent: 6119003 (2000-09-01), Kukkohovi
patent: 6205334 (2001-03-01), Dent
patent: 6243588 (2001-06-01), Koorapaty et al.
Brown Charles D.
Greenhaus Bruce W.
Qualcomm Incorporated
Tran Congvan
Trost William
LandOfFree
System and method for establishing a communication link... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for establishing a communication link..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for establishing a communication link... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3040734