Communications network system including acknowledgement indicating successful receipt of request for reserved communication slots and start time for said reserved communication slots

• US 5,784,597 A
• Filed: 09/22/1995
• Issued: 07/21/1998
• Est. Priority Date: 09/22/1995
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Jam, Mehrban, Chiu, Ran-Fun
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Perveen, Rehana
• Application Number:
  US08/532,918
• Time in Patent Office: 1,033 Days
• Field of Search: 370/17, 370/50, 370/108, 370/94.2, 358/86, 395/329, 395/552, 395/200.08, 395/557
• US Class Current: 713/401
• CPC Class Codes: H04J 1/12 Arrangements for reducing cross-talk between channels in line transmission systems H04B3/32; in cables or lines H04B3/26 - H04B3/30
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/26 combined with the use of different frequencies
• CPC Class Codes: H04N 2007/17381 the upstream transmission being initiated by the user terminal

Abstract

A computer network for high-speed data communication, has a data transmission cable with a root and at least one leaf node wherein the upstream transmission is synchronized by information received on a downstream channel. Each client station receives data on a first frequency band, and transmits data on a second frequency band according to synchronization signals received on the first frequency band. The client station'"'"'s transmission packets may include requests for reserved slots on the second frequency band for subsequent transmissions, and the SCS has a scheduler operable to determine a start time for requested reserved slots, and transmits the start time for the requested reserved slots. The client stations are operable to wait to continue transmission after waiting for the start time.

Claims

1. A computer network for high-speed data communication, comprising:

a data transmission cable having a root and at least one leaf node;

a signal conversion system (SCS) attached to said root;

at least one client station, each attached to a distinct leaf node;

said signal conversion system (SCS) having;

a transmitter that transmits down-stream data onto said cable on a down-stream channel in a first frequency band, and

a receiver that receives data from said at least one client station on an up-stream channel in a second frequency band including data packets from a particular client station transmitted in a contention slot,

wherein said down-stream data includes an acknowledgment of successful transmission of the data packet, wherein said acknowledgment includes an indication of how long the particular client station must wait prior to transmitting remaining data; and

each client station having;

a receiver that receives data on said first frequency band,

logic to coordinate transmission on a second frequency band according to the indication included within the acknowledgment, and

a transmitter that transmits data on a second frequency band.

5. The computer network of claim 1, wherein said first frequency band is lower than 42 MHz and said second frequency band is above 50 MHz.

6. The computer network of claim 1, said transmitter transmits down-stream data alternately on one of a first plurality of additional frequency bands.

7. The computer network of claim 1, wherein said SCS is operable to detect low-activity frequency bands in the below 42 MHz frequency spectrum and is operable to transmit such low-activity frequencies to said client stations on said first frequency band;

wherein said client station having received such low-activity frequency, uses such low-activity frequency for up-stream data.

8. The computer network of claim 1, wherein said transmitter transmits data as multi-bit data symbols and for each symbol a particular bit is used as a control channel for carrying synchronization information thereby enabling said synchronization.

9. The computer network of claim 1, wherein said down-stream and up-stream channels each have a time-domain, and wherein said time-domain is divided into a plurality of slots;

wherein each slot is marked as a contention slot or as a reserved slot;

wherein in a contention slot all of said client stations or a specified subset of said client stations may transmit up-stream data on said up-stream channel; and

wherein only one particular client station may transmit in a particular reserved slot.

10. The computer network of claim 9, wherein if in a contention slot said SCS successfully receives a data packet, said SCS transmits on said down-stream channel, to the client station that transmitted said data packet, an acknowledgement of successful receipt of said data packet.

11. The computer network of claim 10, wherein a client station, if after having transmitted a data packet in a contention slot, the client station does not receive an acknowledgement of successful receipt of said data packet, said client station backs-off and then retransmits said data packet.

12. The computer network of claim 9, wherein a client station, that needs to transmit more data than can fit in one slot, in a contention slot, transmits on said up-stream channel, a request for reservation for a number of subsequent slots;

and wherein said SCS, upon successful receipt of such request for reservation, transmits, on said control channel, an acknowledgement, wherein said acknowledgement includes a delay, wherein said delay indicates to said client station how many slots said client station must wait before transmitting said number of slots, and wherein on said control channel, said SCS indicates to all client stations for said number of slots following said delay, that said slots are reserved slots.

13. The computer network of claim 6, wherein said SCS is operable to detect a first low-activity frequency band in the below 42 MHz frequency spectrum and is operable to transmit said first low-activity frequency to said client stations on said first frequency band;

wherein said client station having received said first low-activity frequency, uses said first low-activity frequency for up-stream data;

wherein said SCS is further operable to detect a second low-activity frequency band in the below 42 MHz frequency spectrum;

wherein said SCS is further operable to transmit to said client stations a request to commence transmissions on said second low-activity frequency.

14. The computer network of claim 9, wherein said synchronization signal is a byte long sequence having a particular pattern and wherein said SCS manipulates all other data transmitted on said control channel such that said particular pattern does not appear other than as said synchronization signal.

2. A method for controlling two-way communication of data on a network, comprising:

transmitting down-stream from a signal conversion system (SCS) to a plurality of client stations an acknowledgment signal intended for a particular client station on a first frequency band, wherein the acknowledgment signal includes a start time;

receiving the acknowledgment signal with the particular client station;

transmitting up-stream from said particular client station to said SCS on a second frequency band, said transmission being timed with respect to said information in dependence upon the start time indicated by said SCS acknowledgment signal.

19. The method of claim 2 further comprising the steps of:

determining in a first spectrum a low-noise band and transmitting the center frequency from the low-noise band from the SCS to the client stations; and

using said center frequency to establish said second frequency band for up-stream transmission.

20. The method of claim 2, wherein each of the up-stream and the down-stream frequency bands have a time-domain, and further comprising the steps of:

dividing the time-domain of said up-stream and down-stream frequency bands into slots;

characterizing each of said slots in said up-stream frequency band as a contention slot or as a reserved slot;

transmitting in said contention slots up-stream requests for reserved slots;

including in said acknowledging transmission a delay count for said reserved slots; and

transmitting by only one of said client stations in any one of said reserved slots;

wherein a client station transmitting a request for reserved slots, upon receiving an acknowledgement of such request, waits said delay count prior to transmitting in said reserved slots.

3. A computer network for high-speed data communication, comprising:

a data transmission cable having a root and at least one leaf node;

a signal conversion system (SCS) attached to said root;

at least one client station, each attached to a distinct leaf node;

each client station having;

a receiver that receives data on said first frequency band; and

a transmitter that transmits up-stream data on a second frequency band, wherein said up-stream data includes requests for reserved slots on said second frequency band for subsequent transmissions;

said signal conversion system (SCS) having;

a scheduler operable to determine a start time for requested reserved slots;

a transmitter that transmits down-stream data onto said cable on a first frequency band, wherein said down-stream data includes acknowledgement of successful receipt of said up-stream data and wherein said acknowledgement includes a delay time indicative of the start time for said requested reserved slots; and

a receiver that receives data from said client stations on a second frequency band;

wherein said down-stream data includes synchronization and acknowledgement signals.

4. A method of operating a high-speed data communications network, comprising:

(a) transmitting from a client station to a signal conversion system (SCS) data including requests for reserved communication slots;

(b) scheduling said reserved communication slots; and

(c) transmitting from said SCS to said client station an acknowledgement indicating the successful receipt of said request and a start time for said reserved communication slots.

15. A method for enabling communication among a plurality of stations connected to a shared channel, comprising the steps of:

dividing the time-domain of said channel into a plurality of slots;

characterizing each slot as a contention slot or as a reserved slot;

permitting a plurality of stations to transmit on a contention slot;

transmitting in said contention slots requests for reserved slots; and

transmitting acknowledgements of successful transmission of data packets transmitted in said contention slots, wherein said acknowledgements include indication of how long a client station requesting reserved slots must wait prior to transmitting in said reserved slots.

16. The method of claim 15, further comprising:

if a station desires to communicate a block of data of such size as to require transmission in n slots, transmitting a first packet containing no more data than what can be transmitted in one slot in a contention slot, and with said first packet transmitting a request for reservation of n-1 slots;

awaiting acknowledgement of receipt of said first packet;

if not obtaining acknowledgement of receipt of said first packet, backing off and retransmitting said first packet, until an acknowledgement of receipt is received by said station;

determining from said acknowledgement a count of slots to wait prior to transmitting the remainder of said block;

waiting said count of slots; and

transmitting the remainder of said block.

17. The method of claim 15, further comprising:

if a station desires to communicate a block of data of such size as to require transmission in n slots, transmitting a first packet containing a request for reservation of n slots;

awaiting acknowledgement of receipt of said first packet;

if not obtaining acknowledgement of receipt of said first packet, backing off and retransmitting said first packet, until an acknowledgement of receipt is received by said station;

determining from said acknowledgement a count of slots to wait prior to transmitting the remainder of said block;

waiting said count of slots; and

transmitting the remainder of said block.

18. The method of claim 15, wherein each packet contains a checksum, further comprising:

checking said checksum, and transmitting said acknowledgement upon successful check of said checksum.