Implementation of delay-critical services in a cable television system
View Patent ↗For transmitting delay-critical data in a digital, time division form in an additional channel of a cable television system, the slots of the channel are further divided into smaller mini slots, for the indication of which the same cyclic indication is used as with which the superframes controlling the use of the channel indicate the original slots. A method based on mini slots is compatible with DAVIC 1.0 and 1.1 specifications.
1. A method for transmitting digital data in an additional channel of a cable television system applying time division multiple access in which slots of a defined slot length are assigned for terminal equipment in order to distribute the use of data transmission capacity to the equipment, and the use of slots in the cable TV system are controlled by use indications transmitted downstream, characterized in that the slots are further divided into mini slots, the use of which is controlled by the indications transmitted downstream, wherein the length of three mini slots plus a guard byte is the same as the defined slot length.
2. A method for transmitting digital data in an additional channel of a cable television system applying time division multiple access in which slots of a defined slot length are assigned for terminal equipment in order to distribute the use of data transmission capacity to the equipment, and the use of slots in the cable TV system are controlled by use indications transmitted downstream, which slots are further divided into mini slots, the use of which is controlled by the indications transmitted downstream, wherein
mini slots are used for the transmission of reservation messages which the terminal equipment use for informing a central configuration that the terminal equipment wish to reserve data transmission capacity, and
the indications transmitted downstream are located in control bytes of at least two slot pairs of a downstream frame and comprise at least indicator flag bits, an upstream transmission permit field and one of the following: a collision feedback information field, an operations, administration and maintenance data field.
3. A central configuration of a cable television system, the central configuration having a receiver for receiving data from terminal equipment of the cable television system in accordance with a time division multiple access principle in which slots of a defined slot length are assigned for terminal equipment in order to distribute use of data transmission capacity to the terminal equipment, and the central configuration having a control for controlling use of slots in the cable television system by transmitting indications downstream, the slots being further divided into mini slots, the control for controlling use of mini slots by transmitting indications downstream,
wherein the central configuration has a receiver for receiving from the terminal equipment reservation messages which the terminal equipment use for informing the central configuration that the terminal equipment wish to reserve data transmission capacity, and wherein the control is arranged to transmit indications downstream in control bytes of at least two slot pairs of a downstream frame, and to include in said indications at least indicator flag bits, an upstream transmission permit field and one of the following: a collision feedback information field, an operations, administration and maintenance data field.
4. Terminal equipment of a cable television system, the terminal equipment having a transmitter for transmitting data to a central configuration of the cable television system in accordance with a time division multiple access principle in which slots of a defined slot length are assigned for terminal equipment in order to distribute use of data transmission capacity to the terminal equipment, and the terminal equipment being adapted to accept control of use of slots in the cable television system by indications transmitted downstream and received by a receiver of said terminal equipment, the slots being further divided into mini slots, and the terminal equipment being adapted to accept control of use of mini slots by indications transmitted downstream and received by said receiver,
wherein the transmitter of the terminal equipment is for transmitting to the central configuration reservation messages which the terminal equipment uses for informing the central configuration that the terminal equipment wishes to reserve data transmission capacity, and
the terminal equipment is arranged to receive indications transmitted downstream in control bytes of at least two slot pairs of a downstream frame and to read from said indications at least indicator flag bits, an upstream transmission permit field and one of the following: a collision feedback information field, an operations, administration and maintenance data field.
5. The method of claim 2 , wherein said mini slots each include a unique word and a payload containing a reservation message.
6. The central configuration of claim 3 , wherein said mini slots each include a unique word and a payload containing a reservation message.
7. The terminal equipment of claim 4 , wherein said mini slots each include a unique word and a payload containing a reservation message.
8. The method of claim 5 , wherein said mini slots are of a contentionless type.
9. The central configuration of claim 6 , wherein said mini slots are of a contentionless type.
10. The terminal equipment of claim 7 , wherein said mini slots are of a contentionless type.
11. The method of claim 2 , wherein said mini slots are of a contentionless type.
12. The central configuration of claim 3 , wherein said mini slots are of a contentionless type.
13. The terminal equipment of claim 4 , wherein said mini slots are of a contentionless type.