Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-05-22
2001-06-05
Bost, Dwayne D. (Department: 2744)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S436000, C455S011100
Reexamination Certificate
active
06243585
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to telecommunications in general, and, more particularly, to: (1) a packet-switched wireless telecommunications network in which the facilities composing the network are mobile, and (2) a set of protocols for reliably routing packets through the network while the topology of the network is changing.
BACKGROUND OF THE INVENTION
FIG. 1
depicts a schematic diagram of a portion of a wireless telecommunications system in the prior art, which system provides wireless telecommunications service to a number of wireless terminals (e.g., wireless terminals
101
-
1
through
101
-
3
) that are situated within a geographic region. The heart of a typical wireless telecommunications system is a wireless switching center (“WSC”), which also may be known as a mobile switching center or mobile telephone switching office. Typically, a wireless switching center (e.g., WSC
120
) is connected to a plurality of base stations (e.g., base stations
103
-
1
through
103
-
5
) that are dispersed throughout the geographic region serviced by the system and to the local and long-distance telephone and data networks (e.g., local-office
130
, local-office
138
and toll-office
140
). A wireless switching center is responsible for, among other things, establishing and maintaining a call between a first wireless terminal and a second wireless terminal or, alternatively, between a wireless terminal and a wireline terminal (e.g., wireline terminal
150
), which is connected to the system via the local and/or long-distance networks.
The geographic region serviced by a wireless telecommunications system is partitioned into a number of spatially distinct areas called “cells.” As depicted in
FIG. 1
, each cell is schematically represented by a hexagon. In practice, however, each cell has an irregular shape that depends on the topography of the terrain surrounding the cell. Typically, each cell contains a base station, which comprises: (1) the radios and antennas that the base station uses to communicate with wireless terminals in that cell; and (2) the transmission equipment that the base station uses to communicate with the wireless switching center.
For example, when a user of wireless terminal
101
-
1
desires to transmit information to a user of wireless terminal
101
-
2
, wireless terminal
101
-
1
transmits a packet bearing the user's information to base station
103
-
1
. The packet is then relayed by base station
103
-
1
to wireless switching center
120
via wireline
102
-
1
. Because wireless terminal
101
-
2
is in the cell serviced by base station
103
-
1
, wireless switching center
120
returns the packet back to base station
103
-
1
, which relays it to wireless terminal
101
-
2
.
The demand for wireless service is never uniform throughout a geographic region. For example, the demand for service is likely to be greater in urban areas and along highways than in wilderness areas. Furthermore, the demand for wireless service in any area changes with the time of day, the day of the week, the seasons of the year, and other factors. For example, a parade or football game or traffic jam can corral a large number of people with wireless terminals into a small area, which temporarily increases the demand in that area.
In practice, the base stations in a wireless telecommunications system are traditionally positioned throughout a geographic region without consideration for where in that region the demand for wireless service will be heaviest or lightest. Instead, base stations are typically positioned uniformly throughout a geographic region (e.g., one base station every 5 miles) in such a manner that each base station services an area of approximately equal size. This implies that some base stations will be underutilized while others are heavily utilized and possibly overwhelmed.
In other words, because the base stations are fixed and uniformly dispersed, but the demand for service is not, there will typically be a mismatch between where the base stations exist and where they are needed. This causes the owner of the wireless telecommunications system to lose money in two ways. First, if the demand for service in an area is not met, then the owner cannot charge for service that is not provided. Second, the owner must spend considerable sums of money on base stations that are underutilized.
One solution is to position more base stations in those areas in which the demand for service is expected to be higher (e.g., at a football stadium). But if the demand for service varies with time in those areas, the base stations in those areas will spend a considerable percentage of the time underutilized. This, as stated above, costs the owner of the wireless telecommunications system to lose money.
Therefore, the need exists for a wireless telecommunications system in which the demand for wireless service is more closely matched by the presence of facilities to meet that demand, even when the demand for service varies with time.
SUMMARY OF THE INVENTION
The present invention is a wireless telecommunications network in which all of the facilities (e.g., wireless switching centers, base stations, etc.) are mobile, and, therefore, are capable of being moved to where they are needed. This allows a wireless service provider to move the facilities into those areas where the demand is high and remove facilities from those areas where the demand is low.
Furthermore, the present invention is particularly advantageous in that all of the various facilities can provide wireless service while the facilities move. In other words, a wireless switching center or base station does not need to be taken out of service, moved, and then brought back online in its new location.
To accomplish this, the illustrative embodiment operates as a packet network in which the wireless switching centers, base stations and wireless terminals are all nodes in the network. Because the illustrative embodiment is a packet network, each wireless switching center and base station contains a routing table, which instructs them how to route packets through the network. And furthermore, because each of the wireless switching centers and base stations are mobile, the illustrative embodiment comprises a set of procedures for updating the various routing tables as the wireless switching centers and base stations are handed off from one to another.
The wireless switching centers and base stations constituting the illustrative embodiment are arranged in a novel network topology, which enables them to move and be handed off without an interruption is service. For example, the wireless switching centers form a ring network, which constitutes the backbone of the illustrative embodiment. Furthermore, each wireless switching center employs one or more base stations that are configured in a hierarchical network.
REFERENCES:
patent: 4539706 (1985-09-01), Mears et al.
patent: 5276686 (1994-01-01), Ito
patent: 5291544 (1994-03-01), Hecker
patent: 5442683 (1995-08-01), Hoogeveen
patent: 5521962 (1996-05-01), Chavez, Jr.
patent: 5729826 (1998-03-01), Gavrilovich
patent: 5787111 (1998-07-01), Gilmore
patent: 5970410 (1999-10-01), Carney et al.
patent: 6021329 (2000-02-01), Kornestedt et al.
“A New Hierarchical Routing Protocol for Dynamic Multihop Wireless Networks” by Ian F. Akyildiz, Wei Yen and Bulent Yener, published prior to May 22, 1998.
Tsai et al., “An Adaptive Hierarchical Routing Protocol”, IEEE Transactions on Computers, vol. 38, No. 8, Aug. 1989.*
Ho et al., “Dynamic Hierarchical Database Architecture for Location Management in PCS Network”, IEEE Transactions on Networking, vol. 5, No. 5, Oct. 1997.*
Veerarghavan, et al., Mobility and Connection Management in a Wireless ATM LAN, IEEE Journal on Selected areas in Communications, vol. 15, No. Jan. 1997.*
Akyildiz et al. “A New Hierarchical Routing Protocol for Dynamic Multihop Wireless Networks”, IEEE 1997.
Pelech James Igor
Yener Bulent
Bost Dwayne D.
Breyer Wayne S.
DeMont Jason Paul
DeMont & Breyer LLC
Lucent Technologies - Inc.
LandOfFree
Wireless telecommunications network whose facilities are... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wireless telecommunications network whose facilities are..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wireless telecommunications network whose facilities are... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2502275