Patent ID: 9179464
Filing Date: 2015-11-03
Classification: H04L,H04W

Abstract:
1. A method for transmitting a reference signal in a wireless communication system, the method comprising: mapping demodulation reference signals (DMRSs) of a first plurality of layers to a first resource element (RE) set and a second RE set, the first RE set and the second RE set each including four REs occupying four orthogonal frequency division multiplexing (OFDM) symbols within a subframe; mapping DMRSs of a second plurality of layers that is different from the first plurality of layers to a third RE set and a fourth RE set each including four REs occupying four OFDM symbols within the subframe; allocating a first orthogonal cover code (OCC) having a length of 4 to each of the DMRSs mapped to the first RE set; allocating a second OCC having a length of 4 to each of the DMRSs mapped to the second RE set; allocating a third OCC having a length of 4 to each of the DMRSs mapped to the third RE set; allocating a fourth OCC having a length of 4 to each of the DMRSs mapped to the fourth RE set; and transmitting the mapped DMRSs, wherein the subframe includes two slots each including six OFDM symbols, wherein the fourth OCC is obtained by swapping positions of bits constituting the third OCC, and wherein the second OCC is obtained by swapping positions of bits constituting the first OCC.