Electrical computers and digital processing systems: multicomput – Computer-to-computer data routing
Reexamination Certificate
2000-01-28
2003-12-30
Jaroenchonwanit, Bunjob (Department: 2143)
Electrical computers and digital processing systems: multicomput
Computer-to-computer data routing
C370S351000
Reexamination Certificate
active
06671735
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The invention relates to wireless communication systems. More particularly, the invention relates to wireless networks.
II. Description of the Related Art
Data networks which provide wired connectivity to a set of users are a vital part of the business, academic and consumer environment today. For example, one of the largest data networks in the world is the Internet. In addition to the Internet, many organizations have private networks to which access is limited to a select number of users. For example, a corporation may have an internal data network which interconnects its computers, servers, dumb terminals, printers, inventories and test equipment using a wired Ethernet topology.
When a system user leaves his desk, he often does not wish to lose his connection to the data network. If the user attends a meeting within his organization, he may wish to bring his computer and print out documents on a local printer. He may also wish to maintain connectivity to the data network while moving between his office and the meeting so that he may, for example, continue to download or print a large file, maintain contact with colleagues, or simply avoid re-initiating the connection when he reaches his final destination. All of the functions can be supported through the use of a distributed wireless data network.
FIG. 1
is a block diagram of a distributed wireless data network architecture. In
FIG. 1
, a series of network access points
12
A-
12
N are distributed throughout a service area. In a typical configuration, each network access point
12
has one or more antennas which provide a corresponding coverage area which abuts one or more coverage areas of other network access points
12
so as to provide a contiguous service area. In the configuration shown in
FIG. 1
, the network access points
12
A-
12
N may provide continuous coverage for a campus of buildings occupied by a single entity.
In the distributed architecture of
FIG. 1
, each of the network access points
12
A-
12
N is a peer to the others and no single network access point
12
is designated as a general controller. The network access points
12
A-
12
N are interconnected by a packet router
14
. The packet router
14
also interconnects the network access points
12
A-
12
N to an external packet switched network
16
which may be another private network or public network such as the Internet. The packet router
14
can be an off-the-shelf product which operates according to an industry standard protocol suite. For example, the packet router
14
may be a CISCO 4700 packet router marketed by Cisco Systems, Inc. of San Jose, Calif., USA. The industry standard packet router
14
operates according to the Internet protocol (IP) suite. In such a configuration, individual entities within each network access point
12
are assigned a unique IP address and, when an entity within a network access point
12
wishes to communicate with another entity within the other network access points
12
A-
12
N or with an entity coupled to the packet switched network
16
, it passes an IP packet to the packet router
14
designating the destination IP address. In addition to the network access points
12
A-
12
N, other entities may be directly wired to the packet router
14
such as printers, computers, test equipment, servers, dumb terminals or any other manner of equipment with data capabilities. These devices are also assigned IP addresses.
Each network access point
12
comprises one or more landside wireless modems which may provide communication with a user terminal
18
. Each user terminal
18
comprises a remote unit wireless modem. For discussion purposes, we assume that the wireless modems within the network access points
12
A-
12
N and user terminal
18
provide a physical layer in accordance with the modulation and multiple access techniques described in the TIA/EIA Interim Standard entitled “Mobile Station—Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,” TIA/EIA/IS-95, and its progeny (collectively referred to here in as IS-95), the contents of which are also incorporated herein by reference or similar subsequent standard. However, the general principles can be applied to many wireless data systems which provide a physical layer interface capable of true mobility.
In
FIG. 1
, each network access point
12
is coupled with control point capabilities. The control point functionality provides mobility management to the system. The control point functionality executes a plurality of functions such as management of the radio link layer, the signaling protocol and data link layer over the wireless link.
In a typical data system, when a user terminal
18
initially establishes communication with the network, it uses a mobile station identifier (MSID). In one embodiment, the user terminal
18
determines the MSID based upon the network access point's electronic serial number or the mobile identification number or other permanent address associated with the user terminal
18
. Alternatively, for increased privacy, the user terminal
18
may select a random number. The user terminal
18
sends an access message to the network access point
12
using the MSID. Using the MSID to identify the user terminal
18
, the network access point
12
and user terminal
18
exchange a series of messages to establish a connection. Once an established, encrypted connection is available, the actual mobile station identification can be transferred to the network access point
12
if a random or other nonfully descriptive MSID has been used.
A temporary mobile station identifier (TMSI) can also be use to identify the user terminal
18
. The TMSI is considered temporary in that it changes from session to session. A new TMSI may be selected when the user terminal
18
enters another system in which the new network access point is not directly coupled to the originating network access point
12
. Also, if power is removed from the user terminal
18
and then reapplied, a new TMSI may be selected.
The originating network access point
12
in which communication is initially established retains in memory the characteristics of the user terminal
18
as well as the current state of the connection. If the user terminal
18
moves to the coverage area of another network access point
12
, it uses the TMSI to identify itself to the network access point
12
. The new network access point
12
accesses a system memory unit
20
in which the originating network access point
12
is identified as associated with the TMSI. The new network access point
12
receives data packets from the user terminal
18
and forwards them to the indicated originating network access point
12
using the IP address specified in the system memory unit
20
.
The process of accessing the system memory unit
20
and managing a centralized pool of TMSIs is cumbersome and consumes system resources. In addition, the process introduces a single point of failure in that a failure of the system memory unit
20
can disable the entire system.
Thus, it will be appreciated that there is a need in the art for a method and system of user terminal identification which is more efficient.
SUMMARY OF THE INVENTION
A first network access point receives a first wireless link message from a first user terminal. The first wireless link message identifies the first user terminal. The first network access point or other system entity assigns an IP address to the first user terminal for use as a temporary mobile station identifier. The first network access point or other system entity installs a route for the IP address to a controller which controls communication with the user terminal. In one embodiment, the controller is within the first network access point. The first network access point forwards a wireless link message to the user terminal specifying the IP address. The first or a second network access point receives another wireless link message from the first user terminal in which the first user te
Baker Kent
Godsey Sandra L.
Jaroenchonwanit Bunjob
Qualcomm Incorporated
Wadsworth Philip
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