Multiplex communications – Communication over free space – Combining or distributing information via time channels
Reexamination Certificate
1998-07-10
2002-06-04
Patel, Ajit (Department: 2662)
Multiplex communications
Communication over free space
Combining or distributing information via time channels
C370S347000, C725S120000
Reexamination Certificate
active
06400705
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method to determine an access frequency band in a communication access network, the communication access network including a plurality of terminals and a head-end which includes a plurality of transceivers, the head-end being downstream coupled to each one of said plurality of terminals via a downstream common link and a tree-like distributive network. It is also directed to, a head-end and a first terminal to realize such a method and a communication access network including such a head-end or such a first.
BACKGROUND OF THE INVENTION
Such a communication access network including such a first 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 Stock 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 to 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 into a predefined frequency bond whereby this transceiver provides a downstream signal to a combiner. The predefined frequency band is associated to this transceiver with a so called predetermined first association. 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 e.g. a first terminal is coupled to at least one receiving transceiver whereof each one is a transceiver as described above. The at least one receiving transceiver is upstream coupled via one common upstream link and at least one individual upstream sublink e.g. a common upstream link from the first terminal to a splitter included in the head-end and at least one individual upstream sublink from the splitter to each receiving transceiver.
It has to be remarked that a plurality of terminals might have upstream access to one and the same receiving transceiver via one and the same common upstream link whereby in a multiple access network terminator a multiple access system e.g. a time division multiple access system or a frequency division multiple access system, is used to give access to this upstream link for each one of the plurality of terminals. However this feature is not a necessary feature.
Since a terminal included in a communication access network as described above is only able to transmit information to the at least one receiving transceiver whereto this terminal is upstream coupled, this terminal needs to know which downstream frequency band, called hereafter the access frequency band, belongs to its access transceiver being one of its receiving transceivers in order to be able to filter out of the modulated downstream signal a downstream signal with this access frequency band and to establish a communication with this access transceiver. Indeed, without prior knowledge of the configuration of the transceivers i.e. the assignment of the downstream 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 rather than the at least 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 access frequency band of its access transceiver to filter out of the received modulated downstream signal a downstream signal which is associated to its access transceiver, the terminal is enabled to establish a communication with its access transceiver.
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 access 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 determine an access frequency band is that each terminal has a different installation configuration according to its access transceiver whereto the terminal is upstream coupled and via which the terminal obtains access to the communication access network. In the event when e.g. such a communication access network needs to be reconfigured due to e.g. an increasing number of terminals coupled to the communication access network and an increasing number of transceivers, the predetermined first association changes and new different downstream frequency bands have to be given to the end-users and each terminal needs to be reconfigured, i.e. tuned on a different new access frequency band.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method to determine an access frequency band to be used by a first terminal such as the above known method but which has not the above drawback of a different installation configuration for each terminal at reconfiguration time of the communication access network.
According to the invention, this object is achieved by a method to determine an access frequency band in a communication access network, the communication access network including a plurality of terminals and a head-end which includes a plurality of transceivers, the 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 to a combiner included in the head-end one of a plurality of downstream signals in one of a plurality of frequency bands associated by means of a predetermined first association to the one of the plurality of transceivers, the plurality of downstream signals being together combined by the combiner 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 at least one receiving transceiver being one of the plurality of transceivers via a common upstream link and at least
Krijntjes Cornelis
Wolters Robert Peter Christina
Alcatel
Patel Ajit
Tran T
Ware Fressola Van Der Sluys & Adolphson LLP
LandOfFree
Method to determine an access frequency band, a head-end and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method to determine an access frequency band, a head-end and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method to determine an access frequency band, a head-end and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2960462