Time-slotted data packets with a preamble

• US 20050271028A1
• Filed: 07/26/2005
• Published: 12/08/2005
• Est. Priority Date: 07/31/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Granted Patent: US 7,889,702 B2
• Time in Patent Office: Days
• US Class Current: 370/345
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

An illustrative embodiment of the present invention supports the transmission of data to a user on an as-needed basis over multiple allocated data channels. Data packets are transmitted in time-slots of the allocated data channels to corresponding target receivers without the need for explicitly assigning particular time-slots to a target user well in advance of transmitting any data packets in the time-slots. Instead, each data packet transmitted in a time-slot includes a header label or preamble indicating to which of multiple possible receivers a data packet is directed. The preamble also preferably includes decoding information indicating how a corresponding data payload of the data packet is to be processed for recapturing transmitted raw data.

Claims

1. A method for communicating data to at least one of a plurality of receivers in a wireless communication system, the method comprising:

allocating at least one channel of multiple available wireless channels to carry time-slotted data packets to a receiver on an as-needed basis; and

providing a preamble in a data packet, the preamble indicating a modulation type used in a transmission of a portion of the data packet.

2. A method as in claim 1, wherein the portion of the data packet is a data payload that is to be decoded by a target receiver to which the data packet is directed.

3. A method as in claim 1, wherein data packets include a data payload for a target receiver and a modulation rate of the data payload is selected from one of multiple possible rates.

4. A method as in claim 3, wherein the modulation rate of the data payload is selected depending on observed link quality parameters of the wireless communication system.

5. A method as in claim 1 further comprising the step of:

encoding bits of the data payload according to a selected forward error correction code, the forward error correction code for a given data packet being selected based on observed link quality parameters of the wireless communication system.

6. A method as in claim 5 further comprising the step of:

providing information in the preamble of a data packet to indicate a forward error correction code of a corresponding data payload of the data packet.

7. A method as in claim 1, wherein the preamble includes address information indicating to which of multiple receivers a data packet is directed.

8. A method as in claim 1 further comprising the step of:

decoding a preamble of received data packet at a receiver to determine a target destination of the data packet.

9. A method as in claim 8 further comprising the step of:

decoding a payload of a received data packet at a target receiver.

10. A method as in claim 1, wherein the preamble indicates a spreading factor used in a transmission of the data payload.

11. A method as in claim 1 further comprising the step of:

providing information in the preamble of a data packet to indicate which of multiple following time-slotted data packets are directed to a target receiver.

12. A method as in claim 1, wherein blocks of data at a transmitter of the wireless communication system are repackaged into smaller blocks that are transmitted over multiple channels in multiple time-slots, so that information in received data packets can be recombined at a target receiver.

13. A method as in claim 1, wherein the channels are forward link channels between a base station and multiple receivers of a CDMA (Code Division Multiple Access) communication system.

14. A method as in claim 1 further comprising:

modulating a preamble of a data packet at a different rate than a data payload portion of the data packet.

15. A method as in claim 1 further comprising:

at a target receiver, combining information received in multiple data packets to reconstruct a network message.

16. A method as in claim 1 further comprising:

assigning a time slot for use by a target receiver by transmitting a message over a dedicated channel for allocating use of wireless resources.

17. A method as in claim 1 further comprising:

at a target receiver, demodulating and decoding a data payload portion of a data packet received in an assigned time slot.

18. A method for receiving data packets on one or more shared channels in a wireless communication system, the method comprising:

synchronizing a receiver to receive data packets transmitted in time-slots of at least one shared data channel;

monitoring a first portion of a received data packet to determine to which receiver of multiple possible receivers sharing an assigned data channel a data packet is directed and a modulation type used in a transmission of a corresponding data payload of the data packet; and

decoding the data payload of the received data packet at a target receiver based on a modulation type as indicated in the first portion of the received data packet.

19. A method as in claim 18, wherein a data payload is decoded according to a selected transmission rate.

20. A method as in claim 18, wherein the data payload is modulated independently of the first portion of the data packet.

21. A method as in claim 20, wherein the data payload is transmitted at a different rate than the first portion of the data packet.

22. A method as in claim 21, wherein the first portion of a given data packet includes specific information that is used for decoding a payload of the corresponding data packet.

23. A method as in claim 18, wherein a modulation rate of the data payload depends on observed link quality parameters of a channel upon which it is transmitted.

24. A method as in claim 18 further comprising the step of:

decoding bits of the data payload according to a selected forward error correction code, the forward error correction code for a given data packet being identified in the first portion of the corresponding data packet.

25. A method as in claim 18, wherein the first portion of a data packet includes information indicating a spreading factor of a data payload.

26. A method as in claim 18 further comprising the step of:

recombining payloads of multiple data packets at a target receiver to reconstruct a network message that is forwarded to a processing device.

27. A method as in claim 18, wherein the shared channels are forward link CDMA (code division multiple access) channels between a base station and multiple receivers.

28. A method of transmitting a data block from at least one base station to one of multiple receivers in a wireless communication system, the method comprising:

reducing the data block into smaller sub-blocks;

producing data packets by appending a header label to each sub-block, the header label of a sub-block indicating how to recapture a corresponding sub-block of a data packet at a receiver; and

at the base station, transmitting the data block via data packets to a target receiver over at least one wireless channel by modulating the sub-block of a data packet according to corresponding information in the header label of a data packet.

29. A method as in claim 28, wherein the at least one wireless channel is shared and the data packets are transmitted on an as-needed basis.

30. A method as in claim 28, wherein the data packets from the base station are transmitted in time slots and the receivers are synchronized to receive data transmitted in the time slots.

31. A method as in claim 28, wherein the shared channels are defined by pseudo-random noise codes of a CDMA (code division multiple access) communication system.

32. A method as in claim 28, wherein a data block is transmitted from a receiver to a base station over shared reverse link channels of a CDMA (Code Division Multiple Access) communication system.

33. A method as in claim 28, wherein a header label includes information indicating a spreading factor of a corresponding sub-block of a data packet.

34. A method as in claim 28, wherein a header label includes information indicating a forward error correction code of a corresponding sub-block of a data packet.

35. A method as in claim 28, wherein a header label includes address information indicating to which of multiple receivers a data packet is directed.

36. A method as in claim 28 further comprising the step of:

combining the data packets at a target receiver to reproduce an original data block.