Patent ID: 9144045
Filing Date: 2015-09-22
Classification: H04J,H04L,H04W

Abstract:
1. A method of transmitting reference signals for synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) system, said method comprising: transmitting a first channel state information (CSI) reference signal in a first slot of a plurality of subframes in accordance with a first configuration of transmission resources, wherein the first configuration of transmission resources defines a first allocation of time and frequency resources for the first CSI reference signal; transmitting a second CSI reference signal in a second slot of one or more of the plurality of subframes in accordance with a second configuration of transmission resources, wherein the second configuration of transmission resources defines a second allocation of time and frequency resources for the second CSI reference signal, and wherein transmitting the first CSI reference signal in accordance with the first configuration and transmitting the second CSI reference signal in accordance with the second configuration comprises transmitting the first and second CSI reference signals from the same antenna port in both the first slot and the second slot of at least a first subframe of the plurality of subframes, wherein the first configuration of transmission resources supports transmission of CSI reference signals from a first set of antenna ports, the second configuration of transmission resources supports transmission of CSI reference signals from a second set of antenna ports having a smaller number of antenna ports than the first set, and the first and second sets of antenna ports include at least one common antenna port for transmission of the first and second CSI reference signals, and wherein transmitting the first CSI reference signal in accordance with the first configuration comprises periodically transmitting the first CSI reference signal in the first slot of two or more subframes with a first repetition frequency, and transmitting the second CSI reference signal in accordance with the second configuration comprises periodically transmitting the second CSI reference signal in the second slot of two or more of the subframes with a second repetition frequency lower than the first repetition frequency.