Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via frequency channels
Reexamination Certificate
1998-07-08
2002-03-19
Yao, Kwang B. (Department: 2664)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via frequency channels
C370S497000
Reexamination Certificate
active
06359907
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method to provide information in a communications access network that includes a plurality of terminals and a head-end having a plurality of transceivers and further being coupled to each one of the terminals via a downstream common link and a tree-like distributive network. It is also directed to a head-end to provide information and a terminal to receive information realizing such a method, and a communication access network including such a terminal and such a head-end.
BACKGROUND OF THE INVENTION
Such a communication access network including such a terminal and such a head-end is already known in the art, e.g. from the submission of “IEEE802.14-95/156, published in Nov. 6, 1995, Protocol Stack and Topology Assumptions for Medium Access Controller (MAC) Level Management Protocol (MLMP) and Medium Access Controller (MAC) Level Access Protocol (MLAP)”. This submission is provided by the IEEE Project 802.14 Working Group/Standard Protocol for Cable-TV Based Broadband Communication Network. Therein a few topology's of multiple communication access networks are introduced, more particular on pages 11, 13 and 15.
In order to indicate the background art which can be regarded as useful for understanding the invention, a description is given of the necessary features of the topology of such a communication access network wherein the invention is used.
Such a communication access network includes a head-end and a plurality of terminals. The head-end and each one of the plurality of terminals are communicating with each other by transmitting downstream and upstream information to each other.
In the downstream direction, the head-end is coupled to the plurality of terminals via a downstream common link and a tree-like distributive network. The head-end includes a plurality of transceivers. Each transceiver receives information from the network which is coupled to this communication access network. Such kind of network is e.g. an asynchronous transfer mode network or a synchronous digital hierarchical network and provides information of e.g. a multimedia server or from a router to an internet provider or information from an other access network. It has to be remarked that the kind of network coupled to a communication access network wherein the invention is used and the kind of information provided by the network coupled to the communication access network of the invention are both no restriction to the invention as such. The aim is that each transceiver included in the head-end receives information. The information received by one of the transceivers is modulated to a predefined frequency band and provided by this transceiver in this predefined frequency band to a combiner. The predefined frequency band is associated to this transceiver. In this way the combiner receives a plurality of downstream signals, each one being provided in a different frequency band. The combiner combines all the downstream signals together into one downstream modulated signal. This downstream modulated signal is broadcasted from the head-end to the plurality of terminals.
In the upstream direction each terminal is coupled to one of the plurality of transceivers included in the head-end via an upstream link. This means that each transceiver has its upstream link and that each terminal has access to the head-end via one of these links.
It has to be remarked that a plurality of terminals might have access to one and the same transceiver via one and the same upstream link whereby e.g. in a network terminator a multiple access system e.g. time division multiple access or frequency division multiple access, is used to give access to this upstream link for each one of the plurality of terminals. However, it will be obvious to a person skilled in the art that this feature is not a necessary feature and that this feature gives no restriction on the scope of the invention.
Since a terminal included in a communication access network as described above is only able to transmit information to the transceiver whereto this terminal is upstream coupled, this terminal needs to known which downstream frequency band belongs to its transceiver in order to be able to filter out of the modulated downstream signal a regenerated downstream signal with this downstream frequency band and to have a proper communication with its transceiver. Indeed, without prior knowledge of the configuration of the transceivers i.e. the assignment of the frequency bands to the transceivers, a situation can occur in which a terminal will react on a downstream signal included in the downstream modulated signal coming from another transceiver than the one that is receiving the upstream information of the terminal. Such a situation can cause an interruption or interference of other transmissions being performed by another terminal connected to another transceiver. Such situations should be prevented. By using the preassigned frequency band of its transceiver to filter out of the received modulated downstream signal a regenerated downstream signal which is associated to the downstream signal provided by its transceiver, the terminal is enabled to communicate with its transceiver in a proper way.
An obvious way to give this knowledge to a terminal of an end-user who likes to establish a communication and to have access to the communication access network is to tune the filter of the terminal to the frequency band according to information given to the end-user by e.g. an operator of the communication access network at e.g. installation time of the terminal.
However, a problem outstanding with this method to provide information concerning a filter frequency band is that each terminal has a different installation configuration according to its transceiver whereto the terminal is upstream coupled. In the event when e.g. an end-user moves with his terminal to another place which is located in an environment of an upstream link coupled to another transceiver his terminal has to be reconfigured according to new information to be given by the operator. Moreover, when such a communication access network needs to be reconfigured due to e.g. an increasing number of terminals coupled to the communication access network, new different frequency bands have to be given to the end-users and each terminal needs to be reconfigured on a different new frequency band.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method to provide information concerning a filter frequency band to be used by a terminal e.g. a first terminal, such as the above known method but which has not the above drawback of a different installation configuration for each terminal.
According to the present invention, this object is achieved by a method for use in a communication access network, the communication access network including a plurality of terminals and a head-end which includes a plurality of transceivers, said head-end being downstream coupled to each one of the plurality of terminals via a downstream common link and a tree-like distributive network, each one of the plurality of transceivers providing one of a plurality of downstream signals, in one of a plurality of frequency bands associated to the one of the plurality of transceivers to a combiner included in the head-end, the plurality of downstream signals being together combined into a downstream modulated signal, the downstream modulated signal being broadcasted from the head-end to the plurality of terminals, a first one of the plurality of terminals being upstream coupled to a first one of the plurality of transceivers via an upstream link, the aim of the method being to provide information to the first terminal, the information concerning a filter frequency band being a first one of the plurality of frequency bands and being intended to be used by the first terminal to filter out of the downstream modulated signal a first regenerated downstream signal associated to a first one of the downstream signals provided by the first transceiver, and wherein t
Vanhoof Harry Franciscus Ludovica
Wolters Robert Peter Christina
Alcatel
Ware Fressola Van Der Sluys & Adolphson LLP
LandOfFree
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