UPLINK RANDOM ACCESS DATA CHANNEL WITH HARQ
Devices and methods are provided for managing random access data channels in a wirelessly-enabled communications environment. An uplink (UL) random access (RA) channel is implemented to send data to an access point (AP) without requiring a UL allocation grant message to be sent on the downlink (DL) for UL timing adjustments. A mobile station (MS) sends a chosen sequence to the AP to indicate that a RA data transmission is being requested. The location and number of radio resources that are used for the UL RA data transmission are determined by the choice of a RA sequence initially sent by the MS. If UL timing has not been established, the AP is able to determine the timing of the UL RA data transmissions by deriving the offset of the initial RA request sequence transmission from the MS.
1 . A system for transmitting data over a random access (RA) data channel comprising:
a plurality of RA data channels, each RA data channel comprising:
a RA sequence associated with a corresponding RA sequence identifier;
a RA resource pattern (RP) comprising a set of uplink (UL) Hybrid Automatic Repeat reQuest (HARQ) transmission opportunities corresponding to a set of data transmission resources, each data transmission resource comprising a set of radio channel resources; and
a mobile station (MS) configured to:
select a RA data channel from the plurality of RA data channels;
transmit the RA sequence associated with the selected RA data channel to an access point (AP);
use the data transmission resources to transmit data to the AP during corresponding HARQ transmission opportunities of the RP associated with the selected RA data channel; and
receive a data transmission positive or negative acknowledgement from the AP.
2 . The system of claim 1 , wherein a number of RA data channels is increased or decreased by the AP according to traffic demand.
3 . The system of claim 1 , wherein a number of data transmission resources allocated to a first RP of the plurality of RPs is greater than a number of data transmission resources allocated to a second RP of the plurality of RPs.
4 . The system of claim 1 , wherein at least one of the data transmission resources from a first set of data transmission resources associated with a first RP of the plurality of RPs is included in a second set of data transmission resources associated with a second RP of the plurality of RPs.
5 . The system of claim 4 , wherein the number of RPs associated with an individual data transmission resource of the set of data transmission resources for a HARQ transmission opportunity varies for each HARQ transmission opportunity in the set of HARQ transmission opportunities.
6 . The system of claim 1 , wherein the set of radio channel resources comprise a restricted subset of the plurality of radio channel resources available on the radio channel.
7 . The system of claim 1 , wherein the AP is configured to re-allocate data transmission resources associated with an RP to other mobile stations when the RA sequence associated with the RP is not received by the AP.
8 . The system of claim 1 , wherein the AP is configured to re-allocate data transmission resources allocated for subsequent HARQ transmission opportunities in the RP to a second mobile station when the data transmission sent in a HARQ transmission opportunity of an RP is successfully decoded and positively acknowledged by the AP.
9 . The system of claim 1 , wherein the data transmission in at least the first HARQ transmission opportunity includes an MS identifier that is encoded or modulated separately from the data transmission.
10 . The system of claim 9 , wherein the AP is configured to signal a response to a data transmission sent during a HARQ transmission opportunity by transmitting an acknowledgement message, the acknowledgment message received by the MS and comprising one or more MS identifiers including at least the MS identifier associated with the data transmission.
11 . The system of claim 1 , wherein the data transmission in the HARQ transmission opportunity includes an MS identifier that is encoded and modulated with the data transmission.
12 . The system of claim 11 , wherein the AP is configured to signal a response to a data transmission sent during a HARQ transmission opportunity by transmitting an acknowledgement message, the acknowledgement message received by the MS and comprising one or more MS identifiers including at least the MS identifier associated with the data transmission.
13 . The system of claim 1 , wherein the AP is configured to communicate an indicator that one or more RA sequences of the plurality of RA sequences has been correctly received by the AP, wherein the indicator is received by the MS and the indicator comprises at least one of the set of:
a bit in an element of a control message associated with one or more of the RA sequences; and
a signal transmitted using a radio resource associated with one or more of the RA sequences.
14 . The system of claim 1 , wherein the AP is configured to communicate an acknowledgement message indicating that one or more RA sequences from the plurality of RA sequences has been correctly received by the AP, the acknowledgement message received by the MS and the acknowledgment message comprises a set of one or more RA sequence identifiers.
15 . The system of claim 1 , wherein the AP is configured to correctly receive the RA sequence and not send a positive acknowledgement message in response.
16 . The system of claim 1 , wherein the AP is configured to communicate an acknowledgment message associated with an RP sent during a HARQ transmission opportunity by transmitting an indicator received by the MS, the indicator comprising at least one of the set of:
a bit in an element of a control message associated with at least the RP; and
a signal transmitted using a radio resource associated with at least the RP.
17 . The system of claim 1 , wherein the AP is configured to communicate an acknowledgement message associated with an RP sent during one HARQ transmission opportunity by transmitting an indicator received by the MS, the indicator comprising a set of RA sequence identifiers including at least the RA sequence identifier associated with the RP.
18 . The system of claim 1 , wherein the AP is configured to confirm the reception of an RA sequence and the allocation of data transmission resources associated with the corresponding RP by transmitting an UL timing advance instruction to the MS.
19 . The system of claim 1 , wherein an individual data transmission resource is an Orthogonal Frequency Division Multiple Access (OFDMA) UL data transmission resource, the OFDMA UL data transmission resource comprising one or more OFDM sub-carriers, an extended guard band, an extended cyclic prefix, a reduced number of symbols, and an extended guard time.
20 . The system of claim 19 , wherein the AP is configured to compute a reception timing offset and use the reception timing offset to synchronize with the data transmissions sent by the MS in HARQ transmission opportunities, the reception timing offset comprising a difference between the start time of an OFDMA subframe and the arrival time of the RA sequence at the AP.
21 . A method for transmitting data over a random access (RA) data channel of a plurality of RA data channels comprising:
associating a RA sequence with a corresponding RA sequence identifier;
providing a RA resource pattern (RP) comprising a set of uplink (UL) Hybrid Automatic Repeat reQuest (HARQ) transmission opportunities corresponding to a set of data transmission resources, each data transmission resource comprising a set of radio channel resources;
selecting a RA data channel from the plurality of RA data channels;
transmitting the RA sequence associated with the selected RA data channel to an access point (AP);
using the set of data transmission resources to transmit data to the AP during corresponding HARQ transmission opportunities of the RP associated with the selected RA data channel; and,
receiving a data transmission positive or negative acknowledgement from the AP.