UMTS: Alive and Well - 4G Americas

Table C.4. Example Predefined Coding Rates. 189Effective Encoding Rate ( R )for CCHs#CE Aggregated(36 RE each)UL Non-Persistent(N payload =38 bits)DL Non-Persistent(N payload = 46 bits)1 0.528 (UL MCS, R~1/2) 0.639 (DL MCS, R~2/3)2 0.264 0.3194 0.132 0.1608 0.066 0.08C.2.2.1.3.1 DL PHYSICAL HARQ INDICATOR CHANNEL (PHICH)The downlink acknowledgment comprises of one-bit control information sent in association with uplinkdata transmission. The resources used for the acknowledgment channel are configured on a semi-staticbasis and are defined independently of the grant channel (i.e. a set of Resource Elements [Res] are semistaticallyallocated for this purpose). Because only one information bit is to be transmitted, a hybrid ofCDM/FDM multiplexing among acknowledgments is used. Hybrid CDM/FDM allows for power controlbetween acknowledgments for different users and provides good interference averaging. In addition, itcan provide frequency diversity for different users. ACK/NACK resource assignment is based on animplicit relationship based on the resource block assignment. With BPSK modulation and I/Q multiplexing,each PHICH channel can carry eight acknowledgments for normal cyclic prefix.C.2.2.1.3.2 DL PHYSICAL CONTROL FORMAT INDICATOR CHANNEL (PCFICH)The PCFICH is used to dynamically indicate the number of OFDM symbols used (n) for control in asubframe. It is transmitted in the first OFDM symbol of the subframe and the three values are indicated bythree sequences of length 16 QPSK symbols. Predefined codewords based on (3, 2) simplex coding withrepetition and systematic bits with dmin=21 is used. To provide maximum frequency diversity, thePCFICH is transmitted over the system bandwidth. Transmit diversity is also supported using the samediversity scheme as the PDCCH. In addition, cell-specific scrambling, tied to the cell ID, is used.C.2.2.1.4LTE DOWNLINK SYNCHRONIZATION CHANNEL STRUCTUREThe DL Synchronization Channel is sent so that the terminals can obtain the correct timing for the DLframe structure, acquire the correct cell, find the number of antennas in BCH and also assist to make189 E-UTRA DL L1/L2 Control Channel Design. 3GPP R1-070787. Motorola RAN1#48. St. Louis. USA. February 2007.www.3GAmericas.org February 2010 Page 167