Multiplex communications – Channel assignment techniques – Combined time and frequency assignment
Reexamination Certificate
1998-04-22
2001-01-23
Rao, Seema S. (Department: 2732)
Multiplex communications
Channel assignment techniques
Combined time and frequency assignment
C370S478000, C370S482000, C370S509000
Reexamination Certificate
active
06178175
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a method for the creation of a data feedback channel in a common frequency network having multi-channel transmission with which the transmitted data are modulated to a plurality of carrier frequencies proximate to each other in frequency space and transmitted in frames separated by synchronization symbols. The invention also concerns a circuit array for carrying out the method and for the realization of a data feedback channel between a receiver having receiver components to a transmitter of a transmitter network in common frequency network operation.
There is a long-felt need for a data feedback channel for use in broadcasting to allow interactive selection of transmitted data from a large data supply or to be able to facilitate billing according to actual media consumption.
Known in the art from WO 94/01825 is a system for the calculation of fees for electronic services. The consumer has a device in which the charges due are compared to a credit amount and subtracted from same to facilitate use of the service. Towards this end, there is a connection between a central computer and the device at the user location.
This system has the disadvantage that two differing types of transmission are selected for bi-directional communication between the user and the central transmission location. In addition, it is not possible to effect interactive operation, since the system is only designed for fee calculation.
Known in the art from WO 92/10038 is a fee calculation system for cable TV with which, similar to WO 94/01825, a device is situated at the user location. This device has the following components: a receiver for a first transmission procedure, a decoder in order to decode the received data, a monitoring circuit to verify the access authorization of the user, a transmitter to transmit data to a central location using a second transmission procedure as well as a demultiplexer for separation of the forward and feedback channels.
This system has the disadvantage that the transmission requires cables and therefore cannot be utilized for mobile receivers. There is the additional disadvantage that two differing transmission procedures are utilized. No information is disclosed with regard to the transmission method itself.
A fee calculation system for a so-called “Value Added Service” is known in the art from EP 601 523 A1 with which an identifier which identifies the data type is added to each data set at a central location and transmitted to the user. The user has a device having individual identification codes and stores the transmitted identifiers. Transmission of a control code by the central location facilitates a request for desired information from the user to the central location which is transmitted along with the identification code.
Disadvantageously, this publication only discloses the fact that the identification code is to be transmitted to associate the transmitted data with a particular terminal. No information is given concerning the transmission protocol used.
Known in the art from EP 595354 A1 is a fee calculation system for broadcasting. This system has a computer located on the transmitter side which stores different types of data, a receiver which receives these data and a transmission format which includes an identifier for each type of data. The receiver thereby comprises circuits for data processing of each data type and a memory for storing the identifiers. The computer transmits conversion data for the calculation of fees in irregular time intervals which are stored in the receiver and utilized together with the identifier for the calculation of fees. Data is transferred by the receiver via a telephone line back to the computer located on the sender side. The receiver requires access authorization previously granted by the computer.
The disclosed fee calculation system has the disadvantage that use requires an additional telephone line for the data feedback channel. Even in the event that such a line is available, additional costs result. In addition, a telephone line has a very small transmission bandwidth so that the transmission capacity is low.
Known in the art from EP 488289 A2 is a cable-related bi-directional video transmission system. A video signal in a base band is mixed to a particular frequency position in the radio frequency range and transmitted along a cable to the receiver. The frequency position of the video signal to be transmitted is determined by a control unit following request by the receiver. The control unit controls the mixer in the transmitter and receiver to effect transmission of the video and request signals within a frequency region which is not in use.
This system has the disadvantage that transmission requires a cable so that it cannot be used by mobile receivers. In addition, there is no description of how to effect high precision synchronization of the mixer in an inexpensive and straightforward fashion.
The purpose of the present invention is to realize a data feedback channel between a mobile radio receiver and a most recently received transmitter, wherein the transmitter and the receiver operate in multi-channel transmission mode within a common frequency network.
SUMMARY OF THE INVENTION
This purpose is achieved in accordance with the invention through a method for the creation of a data feedback channel from a receiver to a transmitter in a common frequency network utilizing a multi-channel transmission with which the transmitted data are modulated to a plurality of carrier frequencies proximate to each other in frequency space and transmitted in frames separated by synchronization symbols, wherein the time and frequency synchronization of the carrier frequencies transmitted in the data feedback channel is effected through evaluation of the carrier frequencies and/or synchronization symbols received in the forward channel. The purpose is also achieved through a circuit configuration for the realization of a data feedback channel between a receiver having receiver components to a transmitter of a transmitter network in common frequency network operation, wherein the output signal is passed to a radio frequency component of the receiver, a component for frequency synchronization as well as a component for time synchronization and the output signals of the components for frequency synchronization and for time synchronization are passed to a component for the production of synchronization signals and a component for the production of data symbols and the component for the production of data symbols comprises an encoder, a generator for the production of COFDM symbols and a modulator.
The method in accordance with the invention has the advantage that the synchronization of frequency and of the transmission time slot in the receiver, which is particularly difficult in a common frequency network, is substantially simplified through evaluation of the received signal. The signal frequency of the transmitter to which a data feedback channel is to be constructed, is utilized to synchronize components in the receiver for determining the transmission frequency of the data feedback channel. In addition, components for time synchronization of the signal transmitted by the receiver in the data feedback channel are controlled using the time sequence of the signal frames received from the transmitter to which a data feedback channel is to be connected.
Advantageous configurations are given in the dependent claims.
The invention is further described and explained below in connection with the embodiment of the drawing.
REFERENCES:
patent: 5392450 (1995-02-01), Nossen
patent: 5452288 (1995-09-01), Rahuel et al.
patent: 5473612 (1995-12-01), Dehner, Jr. et al.
patent: 5509016 (1996-04-01), Muller
patent: 5521926 (1996-05-01), Ayerst et al.
patent: 5617411 (1997-04-01), Mueller
patent: 5644576 (1997-07-01), Bauchot et al.
patent: 5663715 (1997-09-01), Godoroia
patent: 5680398 (1997-10-01), Robinson
patent: 5778318 (1998-07-01), Talarmo et al.
patent: 5956343 (1999-09-01), Cornes et al.
pat
Grundig AG
Rao Seema S.
Vincent Paul
LandOfFree
Circuit array and method for creating a data feedback... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit array and method for creating a data feedback..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit array and method for creating a data feedback... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2486740