Time-slotted data packets with a preamble
View Patent ↗A method and apparatus are used to support the transmission of data to a user 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.
1. A subscriber unit comprising:
circuitry configured to receive a first shared Code Division Multiple Access (CDMA) channel having a first spreading factor, wherein the first shared CDMA channel includes modulation information for a second shared CDMA channel having a second spreading factor, wherein the first spreading factor differs from the second spreading factor;
wherein the circuitry is further configured, on a condition that the first shared CDMA channel is for the subscriber unit, to demodulate the second shared CDMA channel;
wherein the second shared CDMA channel includes packet data and the second shared CDMA channel is received in at least one time slot; and
wherein a portion of the first shared CDMA channel occurs in time prior to the second shared CDMA channel.
2. The subscriber unit of claim 1 , wherein the first shared CDMA channel is received in an unassigned timeslot.
3. The subscriber unit of claim 1 , wherein packet data is received using at least one additional shared CDMA channel.
4. The subscriber unit of claim 1 , wherein a cover sequence associated with the subscriber unit indicates the first shared CDMA channel is for the subscriber unit.
5. The subscriber unit of claim 1 , wherein the first shared CDMA channel and the second shared CDMA channels have different forward error correction (FEC) codings.
6. The subscriber unit of claim 5 , wherein one of the different codings is turbo coding.
7. The subscriber unit of claim 1 , wherein the first shared CDMA channel and the second shared CDMA channel have different modulation types.
8. The subscriber unit of claim 7 , wherein one of the different modulation types is Quadrature Phase Shift Keying (QPSK).
9. The subscriber unit of claim 1 , wherein the circuitry is further configured, on a condition that the first shared CDMA channel is not for the subscriber unit, to not demodulate the second shared CDMA channel.
10. The subscriber unit of claim 5 , wherein the packet data includes a packet that is Internet Protocol (IP) data.
11. The subscriber unit of claim 1 , wherein the second transmission has a duration of 2 milliseconds (ms).
12. The subscriber unit of claim 1 , wherein the circuitry is further configured to receive power control information on a third channel at a same time as receiving at least the second shared CDMA channel.
13. The subscriber unit of claim 12 , wherein the circuitry is further configured to receive synchronization information on the third channel at a same time as receiving at least the second shared CDMA channel.
14. A base station comprising:
circuitry configured to transmit a first shared Code Division Multiple Access (CDMA) channel, having a first spreading factor, for a particular subscriber unit, wherein the first shared CDMA channel includes modulation information for a second shared CDMA channel, having a second spreading factor, for the particular subscriber unit, wherein the first spreading factor differs from the second spreading factor;
wherein the circuitry is further configured to transmit the second shared CDMA channel for the particular subscriber unit, wherein the second shared CDMA channel includes packet data and a modulation associated with the modulation information and is transmitted in at least one time slot; and
wherein a portion of the first shared CDMA channel occurs in time prior to the second shared CDMA channel.
15. The base station of claim 14 , wherein the first shared CDMA channel is transmitted in an unassigned timeslot.
16. A method for use in a subscriber unit, the method comprising:
receiving a first shared Code Division Multiple Access (CDMA) channel having a first spreading factor, wherein the first shared CDMA channel includes modulation information for a second shared CDMA channel having a second spreading factor, wherein the first spreading factor differs from the second spreading factor;
demodulating the second shared CDMA channel on a condition that the first shared CDMA channel is for the subscriber unit;
wherein the second shared CDMA channel includes packet data and the second shared CDMA channel is received in at least one time slot; and
wherein a portion of the first shared CDMA channel occurs in time prior to the second shared CDMA channel.
17. The method of claim 16 , wherein the first shared CDMA channel is received in an unassigned timeslot.
18. A method for use in a base station, the method comprising:
transmitting a first shared Code Division Multiple Access (CDMA) channel, having a first spreading factor, for a particular subscriber unit, wherein the first shared CDMA channel includes modulation information for a second shared CDMA channel, having a second spreading factor, for the particular subscriber unit, wherein the first spreading factor differs from the second spreading factor;
transmitting the second shared CDMA channel for the particular subscriber unit, wherein the second shared CDMA channel includes packet data and a modulation associated with the modulation information and is transmitted in at least one time slot; and
wherein a portion of the first shared CDMA channel occurs in time prior to the second shared CDMA channel.
19. The method of claim 18 , wherein the first shared CDMA channel is transmitted in an unassigned timeslot.