Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1997-08-04
2001-08-07
Pascal, Leslie (Department: 2633)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200
Reexamination Certificate
active
06271951
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to telecommunications networks and is by way of a development of and improvement in the telecommunications networks disclosed in my earlier UK patent application Nos. 2,291,311 (U.S. application Ser. No. 08/498,090, now allowed) and 2,291,299 (U.S. application Ser. No. 08/498,427, now U.S. Pat. No. 5,872,645) which generally relate to an Asynchronous Transfer Mode (ATM) based network system, which patent specifications are hereby incorporated by reference.
In a telecommunications network a large number of end users/customers are connected or connectable to a so-called head-end unit from which data can be received by each customer and to which data may be sent by each customer. In traditional telecommunications networks such data would be in the form of analogue voice signals and more lately in the form of digital signals.
In contrast, in the present day sophisticated network systems there is a requirement to enable data representing numerous kinds of services to be transmitted between the head-end unit and individual customers.
This requirement results in the need to accommodate high volumes of data, i.e. there is a requirement for relatively high overall bandwidth.
This requirement could theoretically be met by simply providing the network with links having the maximum data carrying capacity that is likely to be required under all operating conditions. However, such an approach would be uneconomical in that for much of the time there would be significant excess unused data carrying capacity, i.e. there would be significant redundancy in the system.
My earlier UK patent application Nos. 2,291,311 and 2,291,299 are concerned with the problem of providing capacity in the data links between the head-end unit and the large number of individual customers sufficient to satisfy the customers' requirements whilst at the same time being economical to install.
In the networks of these two earlier patent applications the architecture is designed to handle a large range of volume of customers from a few up to several thousands. This is achieved by arranging customers in groups (typically thirty-two customers) and having them share the ATM bandwidth of a common ATM pipe so that many such groups of customers can co-exist on the same system. These networks are capable of handling up to 50 Mbits of bidirectional traffic for each customer. The network disclosed in UK 2,291,311 is to a significant extent an analogue system whereas that disclosed in UK 2,291,299 is essentially a digital system.
Although both these systems go a significant way towards providing high capacity links between the individual customers and the head-end unit at an economical cost they have operational limitations which the present invention is concerned with overcoming or at least reducing.
In both of these earlier discussed networks there was no interaction between the different groups of thirty-two customers in the sense that any transmission both to and from those customers was within one stream and one stream only. This results in low power NTEs but is inefficient in its use of the network capacity. This has the effect that any broadcast service that needs to be sent to two customers on different streams resulted in two copies of the data being sent, one to each of the streams. This also limits the upstream bandwidth from the customers on one stream to the capacity of that stream only, even it there is spare capacity on one other stream.
Data travelling from the head end towards the customer is called “downstream traffic”, data travelling from the customer towards the network is called “upstream traffic”. There are two types of downstream traffic namely, point to point traffic which goes to one customer only and broadcast traffic which can go to many customers. There is only point to point traffic in upstream traffic.
In the previous systems as disclosed in UK 2,291,311 and UK 2,291,299 the customer's equipment only looked for their own point to point traffic and any broadcast channels they wanted from their own stream. Likewise they could only transmit data upstream on their stream after they had negotiated with the head-end to send a cell on that stream.
SUMMARY OF THE INVENTION
According to the aspect of the present invention broadcast traffic is sent through any stream once and only once and can be accessed by any customer on any stream. Thus it only need be sent once and this means that the system uses the downstream bandwidth more efficiently if it is carrying many broadcast channels.
According to a second aspect of the present invention, some of the point to point traffic to a high usage customer can be sent via other stream(s) than the “normal” stream by treating such traffic as “broadcast traffic” even though it is only accessed by one customer. This allows the customer's normal stream to be loaded with less traffic and thus enables it to carry the traffic for high use customers with less effect on the low use customers and enables the traffic balance to be improved.
According to a third aspect of the present invention some of the upstream traffic from a high usage customer can be sent via other stream(s) than the normal stream. This additional capacity is pre-allocated to customers who are requesting a lot of bandwidth, thus balancing the load between the different streams. This contrasts with the earlier mentioned systems where there is pre-allocation of bandwidth for low level usage and negotiation of bandwidth for high level usage.
The present invention thus provides a system which is kept simple in relation to low volume users but at the same time offers large volume users prompt extra capacity when required.
In such a network system the cost of the network termination equipment (NTE), i.e. the equipment at the customer end, is extremely price sensitive. It is therefore necessary that any hardware modifications that are proposed to be made to such a network, in order to overcome the problems discussed should not significantly increase the cost of the NTE. The implementation of the present invention achieves this objective.
REFERENCES:
patent: 5872645 (1999-02-01), Proctor
patent: 0 425 871 A2 (1991-05-01), None
patent: 2 291 311 A (1996-01-01), None
patent: 2 291 299 A (1996-01-01), None
patent: WO 89/05070 (1989-06-01), None
Kirschstein et al.
Marconi Communications Limited
Pascal Leslie
LandOfFree
Telecommunications network does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Telecommunications network, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telecommunications network will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499800