Methods for Enhanced HARQ Mechanism
Apparatus and methods are provided to enhance HARQ mechanism. The UE repeatedly transmits a data block with a first repetition number and retransmits the data block with a second repetition number. In one embodiment, the first and the second repetition number value are explicitly included in an uplink grant message. In another embodiment, the UE obtains a repetition number value by looking up a repetition number table indexed by the repetition number indicator, which is included in an uplink grant message for the first repetition number and included in a HARQ message for the second repetition number. In yet another embodiment, the UE determines a coverage enhancement degree value, a data block size value and an available transport resource block size. The UE obtains a repetition number by table-look-up based on the coverage-enhancement degree value, the data block size, and the transport resource block size.
1 . A method comprising:
determining a first repetition number by a user equipment (UE) in a wireless system;
repeatedly transmitting a data block by the first repetition number;
receiving a HARQ message that indicates a negative acknowledgement;
determining a second repetition number for a data retransmission of the data block, wherein the second repetition number is different from the first repetition number; and
repeatedly retransmitting the data block by the second repetition number.
2 . The method of claim 1 , wherein the first repetition number is greater than the second repetition number.
3 . The method of claim 1 , wherein the first repetition number value is explicitly included in an uplink grant message for the data transmission.
4 . The method of claim 1 , wherein the second repetition number value is explicitly included in an uplink grant message for the data retransmission.
5 . The method of claim 1 , wherein the determining of the first repetition number involves:
receiving an uplink grant message for the data transmission, wherein the uplink grant message contains a repetition number indicator;
obtaining the first repetition number value by looking up a repetition number table indexed by the repetition number indicator.
6 . The method of claim 1 , wherein the determining of the second repetition number involves:
retrieving a repetition number indicator from the HARQ message; and
obtaining the second repetition number value by looking up a repetition number table indexed by the retrieved repetition number indicator.
7 . The method of claim 1 , further comprising a repetition number lookup procedure involves:
determining a coverage enhancement degree value;
determining a data block size;
obtaining an available transport resource block size; and
obtaining a repetition number based on the coverage enhancement degree value, the data block size, and the transport resource block size.
8 . The method of claim 7 , wherein the first repetition number is determined using the repetition number lookup procedure.
9 . The method of claim 7 , wherein the second repetition number is determined using the repetition number lookup procedure.
10 . A method, comprising:
determining a first repetition number by a base station for a user equipment (UE) in a wireless network;
sending first repetition number information to the UE; and
receiving a data transmission from the UE, wherein a data block is repeatedly transmitted by the first repetition number.
11 . The method of claim 10 , wherein the first repetition number value is explicitly included in an uplink grant for the data transmission.
12 . The method of claim 10 , wherein a repetition number indicator for the first repetition number value is included in an uplink grant message for the data transmission.
13 . The method of claim 10 , further comprising:
sending a HARQ NACK message to the UE upon an unsuccessful decoding of the received data transmission;
sending a second repetition number information to the UE, wherein the second repetition number is different from the first repetition number;
receiving a data retransmission from the UE, wherein the data block is repeatedly retransmitted by the second repetition number.
14 . The method of claim 13 , wherein the second repetition number value is explicitly included in an uplink grant for the data retransmission.
15 . The method of claim 13 , wherein a repetition number indicator for the second repetition number value is included in the HARQ message.
16 . An user equipment (UE) comprising:
a transceiver that transmits an uplink data transmission to a base station and receives a downlink data transmission from the base station;
a HARQ handler that determines a HARQ acknowledgment status for the uplink data transmission based on the detection of the HARQ indicator; and
a repetition number handler that determines a first repetition number for the uplink transmission of a data block, wherein the data block is repeatedly transmitted by the first repetition number, and determines a second repetition number for a data retransmission upon detecting a NACK from a HARQ message, wherein the first repetition number and the second repetition number are different.
17 . The UE of claim 16 , wherein the first repetition number is greater than the second repetition number.
18 . The UE of claim 16 , the first repetition number value is explicitly included in an uplink grant message for the data transmission.
19 . The UE of claim 16 , the second repetition number value is explicitly included in an uplink grant message for the data retransmission.
20 . The UE of claim 16 , the second repetition number value is explicitly included in a HARQ message for the data retransmission.
21 . The UE of claim 16 , wherein the repetition number handler receives a repetition number indicator from an uplink grant message for the data transmission, and determines the first repetition number by looking up a repetition number table indexed by the repetition number indicator.
22 . The UE of claim 16 , wherein the repetition number handler receives a repetition number indicator from the HARQ message, and determines the second repetition number by looking up a repetition number table indexed by the repetition number indicator.
23 . The UE of claim 16 , wherein the repetition number handler determines the first repetition number using a lookup procedure involving:
determining a coverage enhancement degree value for the data transmission;
determining a data block size for the data transmission;
obtaining an available transport resource block size allocated for the data transmission; and
obtaining the first repetition number based on the coverage enhancement degree value, the data block size, and the transport resource block size.
24 . The UE of claim 16 , wherein the repetition number handler determines the second repetition number using a lookup procedure involving:
determining a coverage enhancement degree value for the data retransmission;
determining a data block size for the data retransmission;
obtaining an available transport resource block size allocated for the data retransmission; and
obtaining the second repetition number based on the coverage enhancement degree value, the data block size, and the transport resource block size.