GB2254759A

GB2254759A - Tv access control system

Info

Publication number: GB2254759A
Application number: GB9103172A
Authority: GB
Inventors: Paul Anthony Broadhurst; Martin Roscoe Sellars
Original assignee: Technetix Ltd
Current assignee: Technetix Ltd
Priority date: 1991-02-14
Filing date: 1991-02-14
Publication date: 1992-10-14
Anticipated expiration: 2011-02-14
Also published as: GB2254759B; GB9103172D0

Abstract

A TV access control system comprises a hub unit (10) serving a plurality of groups of customers within a predetermined area. Each group of customers (eg in a block of flats) are served by a headend unit (12) connected to a satellite TV dish (14). The headend unit receives control signals transmitted from an antenna (16) connected to the hub unit (10). The hub unit (10) stores information about the current availability of the TV channels to each customer and transmits control signals to control the de-scrambling means in each customer's customer unit (48). Thus, each customer's ability to receive a premium TV channel is controlled and governed by what is stored in the hub unit (10). <IMAGE>

Description

Title: TV Access Control System Field of the Invention This invention relates to a system for controlling the access to at least one television channel of customers located within a prescribed area.

Background to the Invention The introduction of satellite TV offers the possibility of access to additional channels by customers. Certain channels, called "Premium Channels" limit access to those customers who pay a subscription to the operator, and this limitation is achieved by scrambling the transmitted signal and providing each subscriber with a de-scrambler which de-scrambles the received signal so that the customer's TV set can receive the premium channel. This arrangement works when each individual subscriber has his own receiving dish and his own de-scrambler, but it does not work where a single receiving dish serves a number of customers, for example in a block of flats, some of whom may be subscribers whilst others may be non-subscribers.

The position is further complicated in that some individuals may be subscribers to particular channels and not others. This problem of conditional access has in the past been tackled either by providing for each group of customers a headend which controls the customer's access to the TV channels, or by the use of a pre-pay card access system. Both these systems have significant disadvantages which the present invention aims to overcome.

Disclosure of the Invention According to the invention a system for controlling access to at least one television channel of customers located within a prescribed area, comprises a hub unit for serving the area, a plurality of headend units each intended to serve a group of customers each having a customer unit linked by cable to the corresponding headend unit, each headend unit having the facility to scramble incoming signals so as to direct scrambled signals to each customer unit, each customer unit having de-scrambling means to descramble the scrambled TV signals, the hub unit having storage means for storing information concerning the current availability of the TV channels to each customer and having means for transmitting control signals to each headend unit to control the de-scrambling means of each customer unit in dependence upon the current availability of the TV channel to the customer.

Hence, in the invention each customer's ability to receive a premium TV channel is controlled and governed by what is stored in the storage means of the hub unit. The storage means is preferably a database which contains not only subscriber access information but also billing information and records for each customer. Further, the database may include headend records (typically giving the headend address and the programmes offered at the headend) and a subscriber record for each customer, typically detailing the customer's address, channel selection possibilities and account details. The database can be readily altered or up-dated.

Each headend unit preferably has the facility of separately scrambling incoming TV signals on several channels, the storage means then storing the current availability of each TV channel to each customer and the control signals then governing operation of each customer unit so as to control the ability of each customer to receive each TV channel in accordance with the stored information.

The hub unit preferably communicates with each headend unit by a radio link which may be satellite or terrestial.

Alternatively, the hub unit may communicate with each headend unit by a hard-wired link or a combination of hard-wired and radio link. For example, there may be an intermediate hard-wired link respective ends of which communicate by radio with the hub unit and each headend unit.

A TV access control system will now be described, by way of example, with reference to the accompanying drawings which shows the system in block diagram form.

The system comprises a central hub 10 which serves customers within a predetermined area, of the order of 5 miles radius. Within this area there are a plurality of groups of customers with each group being served by a headend such as that shown at 12 in the drawing. For example the occupants of a block of flats might form one such group, the headend 12 then being mounted on or in the roof of the block of flats. A satellite TV dish 14 is mounted on the block of flats to receive a number of TV channels, eight in the example illustrated. The hub 10 has an antenna 16 and the headend 12 is also equipped with an antenna 18. Radio signal are broadcast by the antenna 16 to all of the antennas 18 of the headends 12 located within the end area served by the hub 10. The headends 12 are similar, the illustrated headend 12 being exemplary.

The hub 10 includes an operator's billing system 20 which feeds information to a hub unit 22. The hub unit 22 includes a conditional access controller 24, in practice a computer, which provides storage means which store the current availability of each TV channel to each customer.

The controller 24 is linked to a frequency shift keying data modulator 26 which converts data from the controller 24 into a form suitable for transmission by a data transmitter 28 linked to the transmitting antenna 16.

The data transmitted from the antenna 16 is a 1200 baud per second data stream which controls the ability of each customer to gain access to certain premium channels picked up by the satellite dish 14. The data stream transmitted by the radio link is received by the antenna 18 and fed to a headend unit 30 forming part of the headend 12. The headend unit 30 has a data receiver 32 whence the data is split into two control streams. One stream is fed to a control processor 34 which applies scrambling signals in respective scramblers 36 to each of premium channels marked 5 to 8. The signals from the eight channels 1 to 8 are received by the dish 14 and fed to eight respective satellite receivers 38.The signals from non-premium channels 1 to 4 are supplied directly to respective UHF modulators 40 whilst.signals of the premium channels 5 to 8 are individually de-scrambled in de-scramblers 42 before being scrambled in the scramblers 36 in accordance with the control data received from the hub 10.

The signals from the respective modulators 40 are fed to respective launch amplifiers 43 which feed the TV signals to a conventional distribution system 44 feeding co-axial cables 46 leading, via respective customer units 48, to customers' individual TV sets 50. One such customer unit is shown in greater detail at 48a. Each customer unit is a set-top unit and includes a de-scrambler 52 which is controlled by the second data stream from the receiver 32, the second stream passing through a data modulator 54 before being fed to the distribution system 44 and thence via the co-axial cables 46 to the customer units 48.

An existing SMATV (Satellite Master Antenna TV) headend system can be converted to work in accordance with the invention by the provision of the hub unit 22, the headend 30 and a customer unit 48 (including a de-scrambler 52) for each customer. In the resulting system the hub unit 22 provides the information storage, intelligence and control for the system in that the control signals broadcast by the radio link from the antenna 16 to the antenna 18 determine the ability of each customer's TV set to receive each of the premium channels 5 to 8.

The invention is also applicable to a MATV (Master Antenna TV) system.

The invention thus avoids the need for "intelligent" headends, because the memory and control functions are performed by the central hub 10.

Claims

1. A system for controlling access to at least one television channel of customers located within a prescribed area, the system comprising a hub unit for serving the area, a plurality of headend units each intended to serve a group of customers each having a customer unit linked by cable to the corresponding headend unit, each headend unit having the facility to scramble incoming signals so as to direct scrambled signals to each customer unit, each customer unit having de-scrambling means to de-scramble the scrambled TV signals, the hub unit having storage means for storing information concerning the current availability of the TV channels to each customer and having means for transmitting control signals to each headend unit to control the de-scrambling means of each customer unit in dependence upon the current availability of the TV channel to the customer.

2. A system according to claim 1, wherein the storage means is a database which contains not only subscriber access information but also billing information and records for each customer.

3. A system according to claim 2, wherein the database includes headend records, giving the headend address and the programmes offered at the headend, and a subscriber record for each customer, detailing the customer's address, channel selection possibilities and account details.

4. A system according to any of the prededing claims, wherein each headend unit has the facility of separately scrambling incoming TV signals on several channels, the storage means storing the current availability of each TV channel to each customer and the control signals governing operation of each customer unit so as to control the ability of each customer to receive each TV channel in accordance with the stored information.

5. A system according to any of the preceding claims, wherein the hub unit communicates with each headend unit by a radio link.

6. A system according to claim 5, wherein the radio link is satellite or terrestrial.

7. A system according to any of claims 1 to 4, wherein the hub unit communicates with each headend unit by a; hard-wired link or a combination of hard-wired and radio link.

8. A system for controlling access to at least one television channel of customers located within a prescribed area, the system being substantially as herein particularly described with reference to the accompanying drawing.