Multiplex communications – Network configuration determination – Using a particular learning algorithm or technique
Reexamination Certificate
2000-02-16
2004-08-24
Pham, Chi (Department: 2663)
Multiplex communications
Network configuration determination
Using a particular learning algorithm or technique
C370S351000
Reexamination Certificate
active
06781960
ABSTRACT:
BACKGROUND
The present invention relates generally to radiocommunication systems and, more particularly, to techniques and structures for multi-point to multi-point communications.
The growth of commercial communication systems and, in particular, the explosive growth of cellular radiotelephone systems worldwide, has compelled system designers to search for ways to increase system capacity and flexibility without reducing communication quality beyond consumer tolerance thresholds. Mobile calls for example, may be routed in a circuit switched fashion, a packet switched fashion, or some hybrid thereof. It has become increasingly desirable to couple and to integrate mobile cellular telephone networks, for instance a GSM network, to Internet protocol (IP) networks for call routing purposes. The routing of voice calls over IP networks is frequently termed “voice over IP” or, more succinctly, VoIP.
Packet-switched technology, which may be connection-oriented (e.g., X.25) or “connectionless” as in IP, does not require the set-up and tear-down of a physical connection, which is in marked contrast to circuit-switched technology. This reduces the data latency and increases the efficiency of a channel in handling relatively short, bursty, or interactive transactions. A connectionless packet-switched network distributes the routing functions to multiple routing sites, thereby avoiding possible traffic bottlenecks that could occur when using a central switching hub. Data is “packetized” with the appropriate end-system addressing and then transmitted in independent units along the data path. Intermediate systems, sometimes called routers, stationed between the communicating endsystems systems make decisions about the most appropriate route to take on a per packet basis. Routing decisions are based on a number of characteristics, including: least-cost route or cost metric; capacity of the link; number of packets waiting for transmission; security requirements for the link; and intermediate system (node) operational status.
An exemplary point-to-point packet routing system (also referred to as a Local Multi-point Distribution Service (LMDS) system) is illustrated in FIG.
1
. The LMDS system
100
provides wireless access to fixed networks. The LMDS system
100
includes a number of cells, each of which include a corresponding node
102
,
103
,
104
(e.g., a base station). The nodes
102
,
103
,
104
are each connected to a network
106
, which may be a computer network, a cable television network or a public switched telephone network. Point-to-point interconnections or other transmission links could be used in place of the network
106
to nodes
102
,
103
,
104
. The nodes
102
,
103
,
104
transmit and receive packets to communication devices such as mobile telephone devices used by multiple users
108
.
In the above LMDS system, since each node
102
,
103
,
104
, can communicate only with the users in its transmission range or with the network
106
, a network or node failure will result in undeliverable packets. For example, if the link
107
between node
103
and the network
106
fails, then all packets directed to the users
108
within the transmission range of node
103
will not be delivered. In addition, since there is only link
107
between the node
103
and the network
106
, an increase in packet traffic may exceed the transport capacity of the link
107
. Further, the above LMDS system cannot be easily modified by adding nodes during, for example, a temporary node failure or a sudden increase in packet traffic due to, for example, a stadium or arena event or a disaster site.
SUMMARY
The present invention overcomes the above-identified deficiencies in the art by providing a method and system for multi-point to multi-point communication.
According to a first aspect of the present invention, provided is a multi-point to multi-point system including a plurality of multi-point nodes. Each of the multi-point nodes includes a transmitter that broadcasts over at least one sector; a receiver that receives broadcasts over the sectors; a router; and a memory. Sector identifiers corresponding to each sector are stored in the memory and broadcast over their respective sectors. A link routing table is stored in the memory and informs the router of available communication paths for the multi-point node based on receipt of-at least one sector identifier from another multi-point node. A root multi-point node that communicates with at least one of the multi-point nodes includes a memory that stores at least one sector identifier. The sector identifier is communicated to at least one of multi-point nodes. A root node link routing table is stored in the memory that includes contents of link routing tables from all of the plurality of multi-point nodes.
According to another aspect of the present invention, a multi-point node is provided. The multi-point node includes a transmitter that broadcasts over at least one sector and a receiver which receives broadcasts over the at least one sector. The multi-point node also includes a router and a memory. Sector identifiers corresponding to respective sectors are stored in the memory and broadcast over its corresponding sector. The receiver receives at least one sector identifier each corresponding to a sector of another multi-point node. A link routing table, based on receipt of the at least one sector identifier, is stored in the memory and informs the router of available communication paths for the multi-point node.
According to another aspect of the present invention, a method of operating a multi-point mode is provided. The method includes maintaining a link routing table in each of a plurality of multi-point nodes. Each link routing table includes a sector identifier and a link quality field of all sectors of neighboring multi-point nodes which have a link quality above a predetermined threshold. Each of the link routing tables is transmitted to a root multi-point node.
According to another aspect of the present invention, a method of operating a multi-point mode is provided. The method includes receiving a signal from at least one sector of at least one other multi-point node and measuring the link quality of the received signal. The sector identifier and the link quality values for each received signal is stored in a link routing table if the link quality exceeds a predetermined threshold value. The link routing table is then sent to a root multi-point node.
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George Keith M.
Pham Chi
Telefonaktiebolaget LM Ericsson (publ)
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