Time and frequency synchronization
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsHavish Koorapaty, Mattias Frenne, Daniel Larsson, Jiann-Ching Guey, Jung-Fu Cheng
Life of this patent
Estimating the term…
Abstract
The scheduling flexibility of CSI reference signals enables time and frequency synchronization using multiple non-zero CSI-RSs transmitted in the same subframe, or using CSI-RSs transmitted in the same subframe with other synchronization signals. Also, multiple synchronization signals may be scheduled in the same subframe to enable fine time and frequency synchronization without cell-specific reference signals.
Claims21
A method of transmitting synchronization signals in an Orthogonal Frequency Division Multiplexing (OFDM) system for synchronizing with a periodic radio frame comprising a plurality of subframes, wherein each of the subframes comprises a plurality of slots, said method comprising:
- transmitting a primary synchronization signal in a first subframe of a frame and a second subframe of the frame;
- transmitting a first secondary synchronization signal in a first slot of the first subframe over a first antenna port;
- and
- transmitting a second secondary synchronization signal in a second slot of the first subframe over the first antenna port,
- wherein the secondary synchronization signals are excluded from the second subframe.
A base station in an Orthogonal Frequency Division Multiplexing (OFDM) system, said base station comprising:
- a transceiver circuit configured to communicate with a user terminal over a wireless communicate channel;
- and
- a control circuit providing synchronization signals for transmission to the user terminal via the transceiver circuit, said control circuit being configured to:
- transmit a primary synchronization signal in a first subframe of a frame and a second subframe of a frame;
- transmit a first secondary synchronization signal in a first slot of the first subframe over a first antenna port;
- transmit a second secondary synchronization signal in a second slot of the first subframe over the first antenna port;
- and
- transmit the first secondary synchronization signal and the second secondary synchronization signal on the same antenna port,
- wherein the secondary synchronization signals are excluded from the second subframe.
A method of synchronizing, in an Orthogonal Frequency Division Multiplexing (OFDM) system, with a periodic radio frame comprising a plurality of subframes, wherein each of the subframes comprises a plurality of slots, said method comprising:
- receiving a primary synchronization signal that is transmitted in a first subframe of a frame and a second subframe of the frame;
- receiving a first secondary synchronization signal that is transmitted by a first antenna port in a first slot of the first subframe;
- receiving a second secondary synchronization signal that is transmitted by the first antenna port in a second slot of the first subframe;
- and
- synchronizing with the OFDM system using the primary synchronization, the first secondary synchronization signal, and the second secondary synchronization signal,
- wherein the secondary synchronization signals are excluded in the second subframe.
A user terminal in an Orthogonal Frequency Division Multiplexing (OFDM) system, said user terminal comprising:
- a transceiver circuit configured to communicate with a base station over a wireless communicate channel;
- and
- a control circuit for synchronizing with the OFDM system, said control circuit being configured to:
- receive a primary synchronization signal that is transmitted in a first subframe of a frame and a second subframe of the frame;
- receive a first secondary synchronization signal transmitted over a first antenna port in a first slot of the first subframe;
- receive a second secondary synchronization signal transmitted over the first antenna port in a second slot of the first subframe;
- and
- synchronize with the OFDM system using the first and second synchronization signals,
- wherein the secondary synchronization signals are excluded in the second subframe.
Dependencies are inferred from the claim text.