Patent ID: 8908651
Filing Date: 2014-12-09
Classification: H04L

Abstract:
1. A method of transmitting reference signals in a radio communication system, the method comprising: mapping, for a first antenna group including a plurality of antennas, first reference signals to a set of fixed resource elements (REs) in two slots of a subframe, wherein the first reference signals are frequency division multiplexed on different REs in the set of fixed REs; mapping, for a second antenna group including a plurality of antennas, second reference signals to K last consecutive control channel elements (CCEs) of L CCEs reserved for physical downlink control channel (PDCCH) in N starting orthogonal frequency division multiplexing (OFDM) symbols in a first slot of the subframe, wherein the second reference signals are code division multiplexed on the K last consecutive CCEs using different orthogonal sequences, wherein K≧1, wherein L>K, and wherein 1≦N≦3; and transmitting the first reference signals and the second reference signals at the subframe, wherein each of the L CCEs includes a plurality of resource elements groups (REGs), and wherein the L CCEs are interleaved in a unit of REG.