Method and apparatus for efficient operation of an enhanced dedicated channel
A method and apparatus for efficient operation of an enhanced dedicated channel (E-DCH) are disclosed. A physical layer processing includes computation of various control parameters followed by actual processing of the data to be transmitted. In accordance with the present invention, the computation of the control parameters is performed asynchronously from the associated data operation. A medium access control (MAC) layer provides information needed for computation of the control parameters to the physical layer as early as possible, while the data is being processed in parallel. The provided data includes a hybrid automatic repeat request (H-ARQ) profile, a transport block size, power offset, or the like. By sending this data to the physical layer before MAC-e processing is complete, the latency constraint can be significantly relaxed.
1. A method of transmitting enhanced dedicated channel (E-DCH) data, the method comprising:
sending an interrupt message by a physical layer to a medium access control (MAC) layer;
initiating MAC layer processing by the MAC layer for the E-DCH transmission of the data during a first time period after receiving the interrupt message;
sending a first message to the physical layer by the MAC layer, the first message including information that enables the physical layer to compute control parameters for the E-DCH transmission of the data; and
the physical layer computing the control parameters for the E-DCH transmission of the data during a second time period while the data is being processed by an entity other than the physical layer, the second time period overlapping the first time period.
2. The method of claim 1 , wherein the first message sent to the physical layer for calculating the control parameters includes at least one of: a hybrid automatic repeat request profile, a transport block size, or a transmit power offset for the E-DCH.
3. The method of claim 1 , wherein the physical layer sends the interrupt message to the MAC layer at any one of: each transmission time interval (TTI) for which a hybrid automatic repeat request process is available for transmission, each TTI that new scheduling grant information is received, or every TTI.
4. The method of claim 1 , further comprising:
the MAC layer sending a second message to a protocol data unit (PDU) processor to generate a MAC-e PDU; and
the PDU processor generating the MAC-e PDU based on the second message and sending the MAC-e PDU to the physical layer for transmission via the E-DCH.
5. The method of claim 4 , wherein a total processing delay from the time that the interrupt message is sent to the time that the MAC-e PDU is generated is limited to two milliseconds.
6. The method of claim 1 , wherein the interrupt message includes any one of:
an absolute grant with indication on a condition that it was received with a primary or secondary enhanced uplink radio network temporary identity;
relative grants from serving or non-serving cells;
a hybrid automatic repeat request indicator of previous transmissions;
a current dedicated physical control channel power; or
a clock interrupt.
7. A method of transmitting enhanced dedicated channel (E-DCH) data, the method comprising:
sending an interrupt message by a physical layer to a medium access control (MAC) layer;
initiating MAC layer processing by the MAC layer for the E-DCH transmission of the data during a first time period after receiving the interrupt message;
sending a first message to the physical layer by the MAC layer, the first message including information that enables the physical layer to compute control parameters for the E-DCH transmission of the data;
the physical layer computing the control parameters for the E-DCH transmission of the data during a second time period while the data is being processed by an entity other than the physical layer, the second time period overlapping the first time period;
sending a second message by the MAC layer to a radio link control (RLC) layer;
generating an RLC protocol data unit (PDU) based on the second message by the RLC layer and sending the RLC PDU to the MAC layer; and
generating a MAC-e PDU by the MAC layer and sending the MAC-e PDU to the physical layer for transmission via the E-DCH.
8. The method of claim 7 , wherein the first message sent to the physical layer for calculating the control parameters includes at least one of: a hybrid automatic repeat request profile, a transport block size, or a transmit power offset for the E-DCH.
9. The method of claim 7 , wherein the physical layer sends the interrupt message to the MAC layer at any one of: each transmission time interval (TTI) for which a hybrid automatic repeat request process is available for transmission, each TTI that new scheduling grant information is received, or every E-DCH TTI.
10. The method of claim 7 , wherein a total processing delay from the time that the interrupt message is sent to the time that the MAC-e PDU is generated is limited to two milliseconds.
11. A wireless transmit/receive unit (WTRU) for transmitting enhanced dedicated channel (E-DCH) data, the WTRU comprising:
a physical layer processor configured to send an interrupt message to a medium access control (MAC) layer;
the MAC layer configured to:
initiate a MAC layer processing for the E-DCH transmission of the data during a first time period after receiving the interrupt message; and
send a first message to the physical layer processor, the first message including information that enables the physical layer processor to compute control parameters for the E-DCH transmission of the data; and
the physical layer processor being further configured to compute the control parameters for the E-DCH transmission of the data during a second time period while the data is being processed by an entity other than the physical layer processor, the second time period overlapping the first time period.
12. The WTRU of claim 11 , wherein the first message sent to the physical layer processor for calculating the control parameters includes at least one of: a hybrid automatic repeat request profile, a transport block size, or a transmit power offset for the E-DCH.
13. The WTRU of claim 11 , wherein the physical layer processor is configured to send the interrupt message to the MAC layer at any one of: each transmission time interval (TTI) for which a hybrid automatic repeat request process is available for transmission, each TTI that new scheduling grant information is received, or every E-DCH TTI.
14. The WTRU of claim 11 , wherein:
the MAC layer is further configured to send a second message to a protocol data unit (PDU) processor for generating a MAC-e PDU; and
the PDU processor is configured to:
generate the MAC-e PDU based on the second message received from the MAC layer; and
send the MAC-e PDU to the physical layer processor for transmission via the E-DCH.
15. The WTRU of claim 11 , wherein:
the MAC layer is further configured to send a second message to a radio link control (RLC) layer to generate an RLC protocol data unit (PDU);
the RLC layer is configured to:
generate the RLC PDU based on the second message received from the MAC layer; and
send the RLC PDU to the MAC layer; and
the MAC layer is further configured to:
generate a MAC-e PDU based on the RLC PDU generated by the RLC layer; and
send the MAC-e PDU to the physical layer processor for transmission via the E-DCH.