Distribution of cell-common downlink signals in a hierarchical heterogeneous cell deployment

摘要

A high-power point (110) and one or more low-power points (120) transmit signals that are associated with the same cell-identifier in a heterogeneous cell deployment. The coverage areas corresponding to the low-power points (120) fall at least partly within the coverage area for the high-power point (110), so that mobile stations (130) within range of a low-power point are also within range of the high-power point (110), from a downlink perspective. The same CRS signals are transmitted by both the high-power (macro) point (110) and some or all of the low-power (pico) points (120). At the same time, the network transmits CRS-based PDSCH for a particular UE on both the high-power point (110) as well as on some or all of the low-power points (120). In some embodiments only a subset of the points, e.g., those points that the UE hears sufficiently well, participate in the PDSCH transmission using CRS for channel estimation.

主权项

1. A method for transmitting data to a mobile station, the method comprising
transmitting cell-specific reference symbol (CRS) signals from a primary, high-power, transmitting node having a first coverage area; transmitting the same CRS signals from each of two or more secondary, low-power, transmitting nodes, each of the secondary transmitting nodes having a coverage area that is within or substantially within the first coverage area; simultaneously transmitting a physical downlink data channel to a mobile station from the primary, high-power, transmitting node and from at least one of but fewer than all of the two or more secondary, low-power, transmitting nodes, wherein said at least one but fewer than all of the two or more secondary, low-power, transmitting nodes is selected based on a determination of whether the physical downlink data channel transmissions from each secondary transmitting node could be received by the mobile station with adequate signal strength; and monitoring traffic load at each of said secondary transmitting nodes; and selectively powering on and powering off transmissions of the CRS signals at each secondary transmitting node, based on the corresponding traffic load.