Method and apparatus for allocating resources for an enhanced physical hybrid automatic repeat request indicator channel

Abstract

A method and apparatus are described for allocating resources for an enhanced physical hybrid automatic repeat request (HARQ) channel (E-PHICH). A subset of an enhanced physical downlink control channel (E-PDCCH) may be allocated for use by the E-PHICH. The E-PDCCH may be defined by at least one of enhanced resource element groups (eREGs) and enhanced control channel elements (eCCEs). Each eCCE may be formed by grouping a plurality of eREGs. Each eREG may contain at least one resource element (RE). Alternatively, a subset of eREGs may be allocated as E-PHICH resources. E-PDCCH physical resource block (PRB) pairs may be selected as a resource for the E-PHICH. An indication of the number of the eCCEs may be broadcast to a wireless transmit/receive unit (WTRU).

What is claimed: 
     
         1 . A method of allocating resources for an enhanced physical hybrid automatic repeat request (HARQ) channel (E-PHICH), the method comprising:
 allocating a subset of an enhanced physical downlink control channel (E-PDCCH) for use by the E-PHICH, wherein the E-PDCCH is defined by at least one of enhanced resource element groups (eREGs) and enhanced control channel elements (eCCEs), each eCCE is formed by grouping a plurality of eREGs, and each eREG containing at least one resource element (RE).   
     
     
         2 . The method of  claim 1  further comprising:
 selecting E-PDCCH physical resource block (PRB) pairs as a resource for the E-PHICH. 
 
     
     
         3 . The method of  claim 2  further comprising:
 broadcasting an indication of the number of the eCCEs to a wireless transmit/receive unit (WTRU). 
 
     
     
         4 . The method of  claim 2  further comprising:
 indicating the number of the eCCEs in each of a plurality of subframes. 
 
     
     
         5 . The method of  claim 2  further comprising:
 configuring the eCCEs via higher layer signaling. 
 
     
     
         6 . The method of  claim 1  further comprising:
 transmitting HARQ positive acknowledgement (ACK)/negative acknowledgement (NACK) information bits via the E-PHICH in accordance with a repetition factor. 
 
     
     
         7 . The method of  claim 6  wherein two ACK/NACK information bits are transmitted per E-PHICH. 
     
     
         8 . The method of  claim 1  wherein the E-PHICH contains localized or distributed resource blocks (RBs). 
     
     
         9 . The method of  claim 8  further comprising:
 a wireless transmit/receive unit determining an E-PHICH region. 
 
     
     
         10 . The method of  claim 9  wherein a starting resource block (RB) location and the number of RBs allocated to E-PHICH transmission are indicated when the E-PHICH contains localized RBs. 
     
     
         11 . The method of  claim 9  wherein a bitmap indicating resource blocks (RBs) of resource block groups (RBGs) are indicated when the E-PHICH contains distributed RBs. 
     
     
         12 . A method of allocating resources for an enhanced physical hybrid automatic repeat request (HARQ) channel (E-PHICH), the method comprising:
 allocating a subset of enhanced resource element groups (eREGs) as E-PHICH resources, wherein each eCCE is formed by grouping a plurality of eREGs, each eREG containing at least one resource element (RE).   
     
     
         13 . The method of  claim 12  further comprising:
 using the remaining eREGs for an enhanced physical downlink control channel (E-PDCCH). 
 
     
     
         14 . The method of  claim 13  further comprising:
 broadcasting an indication of the number of the eCCEs to a wireless transmit/receive unit (WTRU). 
 
     
     
         15 . The method of  claim 13  further comprising:
 indicating the number of the eCCEs in each of a plurality of subframes. 
 
     
     
         16 . The method of  claim 13  further comprising:
 configuring the eCCEs via higher layer signaling. 
 
     
     
         17 . A wireless transmit/receive unit (WTRU) comprising:
 a receiver configured to receive an enhanced physical hybrid automatic repeat request (HARQ) channel (E-PHICH), wherein a subset of an enhanced physical downlink control channel (E-PDCCH) is allocated for use by the E-PHICH, the E-PDCCH is defined by at least one of enhanced resource element groups (eREGs) and enhanced control channel elements (eCCEs), and each eCCE is formed by grouping a plurality of eREGs, each eREG containing at least one resource element (RE).   
     
     
         18 . The WTRU of  claim 17  wherein the receiver is further configured to receive a broadcast indicating the number of the eCCEs. 
     
     
         19 . The WTRU of  claim 17  wherein the E-PHICH contains localized or distributed resource blocks (RBs). 
     
     
         20 . The WTRU of  claim 17  further comprising a processor configured to determine an E-PHICH region.