Interactive applications

Abstract

An interactive broadcast system comprising a plurality of user interfaces each comprising a local clock signal generator. Each user interface delivers interactive applications to a respective user with reference to its respective local clock signal. A central control system broadcasts data to the user interfaces. The ccs detects adjustment of the local clock signals to identify fraudulent users.

Description

This enables the CPU 25 to calculate CCS CLOCK at any time as:
CCS CLOCK−STB CLOCK+OFFSET.

Before, at or even after the start of the quiz game, the CCS 2 transmits a game start clock signal CCS CLOCK (game start) to the user interfaces defining the time according to the CCS at which the game starts. The CPU 25 in each STB can then calculate the STB game start time as:
STB CLOCK (game start)·CCS CLOCK (game start)−OFFSET.

During the quiz game, the CCS 2 retrieves question and answer data from the store 3 and places the data on the transport stream 30 before it is to be displayed by the user interfaces. Each item of data contains question/answer data, and also a relative game time (i.e. a time from the start of the game) at which the data is to be displayed. For instance the following sequence of data may be broadcast during a quiz game:

Data       Relative Game Time

Question A 60 seconds-70 seconds
Answer A   70 seconds-75 seconds
Question B 75 seconds-85 seconds
Answer B   85 seconds-90 seconds

Thus Question A is placed on the transport stream prior to 60 seconds from game start, and is displayed from 60-70 seconds from game start. During that 10 second period the user inputs his answer. At 70 seconds the user interface is locked out and the answer to question A is displayed for the next 5 seconds.

The CPU 25 handles the relative game time messages in the following way. The data and relative game time is input to the CPU 25. The CPU 25 then calculates the STB CLOCK time corresponding with the relative game time as:
STB CLOCK (relative)−STB CLOCK (game start)+relative game time.

Thus the CPU displays Answer A between STB CLOCK (70 seconds) and STB CLOCK (75 seconds).

A fraudulent user can take advantage of this system as follows. This fraudulent user inserts an adjustment module 46 (shown in dotted lines in FIG. 2) to adjust the signal STB CLOCK from the STB clock 41. This could either set STB CLOCK forward or backward by a fixed amount, or could slow down or speed up the rate of STB CLOCK. The adjustment module 46 is enabled by the user after STB CLOCK (game start) has been calculated. As a result the display of any subsequent question or answer data is delayed or advanced when compared to other STBs. By running two user interfaces (one with STB CLOCK adjusted, the other not) the fraudulent user can view the answers on one user interface and enter the correct answers on another user interface before it becomes locked out by the CPU 25 since that CPU 25 will not have reached the relative game time at which lock out occurs.

This fraudulent clock adjustment is detected in one or more of a number of ways as discussed below.

1. Return Path Request

At some point after the game start (either during or after the game) the CCS 2 sends a return path request to the user interfaces, asking them to send an acknowledgment back to the CCS 2 at a certain relative game time. If the acknowledgment from one of the user interfaces is delayed or advanced (when compared to the return time of acknowledgements from the other user interfaces) by more than a predetermined threshold then it is likely that STB CLOCK on that user interface has been adjusted. Therefore that user interface is identified and no prize is issued to the fraudulent user registered with the identified user interface.

2. Return Path Scores

The user interfaces are requested to send their scores back to the CCS 2 at the end of the quiz game. If the return time of the score from one of the user interfaces is delayed or advanced (when compared to the return time of scores from the other user interfaces) by more than a predetermined threshold, then that user interface is identified as a fraudulent interface, and no prize is issued to the user registered with the fraudulent interface.

Optionally, the following method may also be employed.

3. STB CLOCK Monitor

A monitor 50 is provided to monitor STB CLOCK and OFFSET. This could be a separate module or part of the CPU 25. If either of these signals is adjusted then the monitor 50 sends a detection signal to the CPU 25 which informs the CCS 2 with an identification message. Thus if the user either adjusts STB CLOCK immediately after STB (game start) has been calculated; or resets STB CLOCK at the end of the game to attempt to disguise their fraud, then this adjustment will be detected by the monitor 50.

Claims

1. An interactive broadcast system comprising:

a plurality of user interfaces each having a local clock signal generator, wherein each user interface delivers interactive applications to a respective user with reference to its respective local clock signal;

a central control system (ccs) for broadcasting data to the user interfaces and for receiving data from the user interfaces, the ccs being adapted to identify fraudulent adjustment of one of the local clock signals by comparing the time of receipt by the ccs of certain data sent by one of the user interfaces with the time of receipt of data from another different one of the user interfaces;

means for periodically broadcasting a central clock signal to the user interfaces; and

each user interface having means for calculating an offset signal with reference to the central clock signal and its respective local clock signal so as to enable obtaining the central clock signal from the local clock signal.

2. A system according to claim 1, wherein each user interface comprises a monitor for detecting adjustment of the local clock signal.

3. A system according to claim 1, wherein the ccs is adapted to send a return path request to the user interfaces and to monitor the time of receipt of corresponding return path data generated by the user interfaces in response to the return path receipt to identify user interfaces which have sent return path data which is advanced or delayed by more than a predetermined threshold.

4. A system according to claim 1, wherein the return path request causes the user interfaces to return a local score at the end of an interactive application as determined by the user interface.

5. A system according to claim 1, wherein the ccs is adapted to broadcast an application start signal to the user interfaces, wherein each user interface comprises means for calculating an application time local clock signal with reference to the application start signal, and wherein each user interface delivers interactive applications to a respective user with reference to its respective application time local clock signal.

6. A method of detecting fraudulent users in an interactive broadcast system, the method comprising:

(1) broadcasting data to a plurality of user interfaces from a central control system (ccs);

(2) generating a local clock signal at each user interface;

(3) delivering an interactive application to a respective user from each user interface with reference to its respective clock signal;

(4) receiving data at the ccs from the local user interfaces;

(5) identifying fraudulent adjustment of one of the local clock signals by comparing the time of receipt by the ccs of certain data sent by one of the user interfaces with the time of receipt of data from another different one of the user interfaces;

(6) periodically broadcasting a central clock signal to the user interfaces; and

(7) calculating at the user interface an offset signal with reference to the central clock signal and a respective local clock signal so as to enable obtaining the central clock signal from the local clock signal.

7. A method according to claim 6, wherein step (4) comprises first sending a return path request to the user interfaces; and

step (5) comprises monitoring the time of receipt of return path data generated by the user interfaces in response to the return path request to identify user interfaces which have sent return path data which is advanced or delayed by more than a predetermined threshold.

8. A method according to claim 6 wherein the return path request causes the user interfaces to return a local score at the end of an interactive application as determined by the user interface.

9. A method according to claim 6, further comprising

(8) broadcasting an application start signal to the user interfaces; and

(9) calculating an application time local clock signal with reference to the application start signal,

wherein each user interface delivers interactive applications to a respective user with reference to its respective application time local clock signal.

10. A method of detecting fraudulent users in an interactive broadcast system, the method comprising:

(1) broadcasting data to a plurality of user interfaces from a central control system (ccs);

(2) generating a local clock signal at each user interface;

(3) delivering an interactive application to a respective user from each user interface with reference to its respective local clock signal;

(4) receiving data at the ccs for the local interface;

(5) identifying fraudulent adjustment of one of the local clock signals by comparing the time of receipt by the ccs of certain data sent by one of the user interfaces with the time of receipt of data from another different one of the user interfaces;

(6) periodically broadcasting a central clock signal to the user interfaces; and

(7) calculating an offset signal at the user interface with reference to the central clock signal and a respective local clock signal so as to enable obtaining the central clock signal from the local clock signal.