Dynamically beamformed control channel for beamformed cells

Abstract

Disclosed herein are apparatuses, systems, and methods using or implementing dynamic beamforming in control channels, by transmitting downlink control channels to user equipment (UEs) in a number of orthogonal frequency division multiplexing (OFDM) symbols of a downlink subframe. A first OFDM symbol of the number of OFDM symbols can be transmitted using first beamforming parameters in a first direction, and a second OFDM symbol of the number of OFDM symbols can be transmitted using second beamforming parameters different from the first beamforming parameters and in a second direction different from the first direction. The number of OFDM symbols used, as well as other parameters, can be dynamically adjusted in subsequent subframes. Other embodiments are described.

1 - 26 . (canceled) 
     
     
         27 . An apparatus for an Evolved Node-B (eNB), the apparatus comprising hardware processing circuitry and transceiver circuitry, the hardware processing circuitry to configure the transceiver circuitry to:
 transmit downlink control channels to user equipment (UEs) in orthogonal frequency division multiplexing (OFDM) symbols of a downlink subframe, a first of the OFDM symbols configured to be transmitted using first beamforming parameters in a first direction, and a second of the OFDM symbols is configured to be transmitted using second beamforming parameters different from the first beamforming parameters and in a second direction different from the first direction.   
     
     
         28 . The apparatus of  claim 27 , wherein the eNB is configured to dynamically adjust beam direction of the OFDM symbols in subsequent subframes based on cell conditions in a cell served by the eNB. 
     
     
         29 . The apparatus of  claim 27 , wherein a search space for a downlink control channel is limited to one OFDM symbol. 
     
     
         30 . The apparatus of  claim 27 , wherein the first OFDM symbol is transmitted according to a demodulation reference signal (DM-RS) pattern in which four resource elements (REs) are reserved for DM-RS, in two sets of two contiguous REs, and wherein four REs are reserved for other than DM-RS between the two sets of contiguous REs. 
     
     
         31 . The apparatus of  claim 30 , wherein the second DM-RS pattern is varied from the first DM-RS pattern according to a cell-specific frequency shift pattern. 
     
     
         32 . The apparatus of  claim 27 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 transmit the first OFDM symbol to a first group of UEs close to the cell edge and the second OFDM symbol to a second group of UEs further from the cell edge than is the first group of UEs.   
     
     
         33 . The apparatus of  claim 27 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 transmit an uplink-formatted downlink control indicator (DCI) in a first analog beam direction on a first OFDM symbol and a downlink DCI in a second direction and in the first OFDM symbol.   
     
     
         34 . The apparatus of  claim 27 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 transmit, in UE-specific DCI, an indication of the number of OFDM symbols in which the control channels are to transmitted.   
     
     
         35 . The apparatus of  claim 34 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 dynamically adjust, between subframes, the number of OFDM symbols in which the control channels are to be transmitted.   
     
     
         36 . The apparatus of  claim 27 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 transmit, in a secondary synchronization signal (SSS), an indication of the number of OFDM symbols in which the control channels are to be transmitted.   
     
     
         37 . The apparatus of  claim 27 , wherein the hardware processing circuitry is further to configure the transceiver circuitry to:
 adjust, upon a UE entering or leaving the cell, the number of OFDM symbols used for transmission of the control channels.   
     
     
         38 . The apparatus of  claim 27 , further including eight or more antennas. 
     
     
         39 . The apparatus of  claim 27 , further including antennas configured in a sub-array based hybrid antenna architecture (HAA). 
     
     
         40 . The apparatus of  claim 27 , wherein the downlink control channels are time-division duplexed with data channels within a subframe. 
     
     
         41 . An apparatus for a User Equipment (UE), the apparatus comprising transceiver circuitry and hardware processing circuitry, the hardware processing circuitry to configure the transceiver circuitry to:
 scan a number of orthogonal frequency division multiplexing (OFDM) symbols of a downlink subframe to detect the highest-energy OFDM symbol of the number of OFDM symbols; and   decode a downlink control channel, in the highest-energy OFDM symbol, the downlink control channel being received in no more than one OFDM symbol from an evolved Node-B (eNB).   
     
     
         42 . The apparatus of  claim 41 , wherein the hardware processing circuitry further configures the transceiver circuitry to:
 receive a value for the number of OFDM symbols to be scanned.   
     
     
         43 . The apparatus of  claim 42 , wherein the value for the number of OFDM symbols to be scanned is received in downlink control information (DCI). 
     
     
         44 . The apparatus of  claim 42 , wherein the value for the number of OFDM symbols to be scanned is received in a synchronization signal. 
     
     
         45 . The apparatus of  claim 41 , wherein, when a relative distance to the eNB changes, the hardware processing circuitry is further to configure the transceiver circuitry to:
 rescan the number of OFDM symbols to detect whether the highest-energy OFDM symbol has changed.   
     
     
         46 . The apparatus of  claim 41 , wherein the hardware processing circuitry further configures the transceiver circuitry to:
 receive uplink-formatted downlink control information (DCI) in a first OFDM symbol of the number of OFDM symbols and downlink DCI in a different OFDM symbol than the first OFDM symbol.   
     
     
         47 . The apparatus of  claim 41 , wherein, when the UE does not receive a value for the number of OFDM symbols, the hardware processing circuitry is further to configure the transceiver circuitry to blind search up to a threshold number of OFDM symbols to detect control channel information. 
     
     
         48 . The apparatus of  claim 41 , wherein the hardware processing circuitry includes a baseband processor to process the control channels. 
     
     
         49 . A computer-readable medium that stores instructions for execution by one or more processors to perform operations for communication by an Evolved Node-B (eNB), the operations to configure the one or more processors to:
 detect locations for user equipments (UEs) in a cell served by the eNB; and   transmit downlink control channels to the UEs in a number of orthogonal frequency division multiplexing (OFDM) symbols of a downlink subframe, the number being set based on at least one of cell load and locations for the UEs.   
     
     
         50 . The computer-readable medium of  claim 49 , wherein a downlink control channel of the plurality of control channels is transmitted in no more than one OFDM symbol. 
     
     
         51 . The computer-readable medium of  claim 49 , wherein the first OFDM symbol is transmitted according to a first demodulation reference signal (DM-RS) pattern and the second OFDM symbol is transmitted according to a second DM-RS pattern different from the first DM-RS pattern. 
     
     
         52 . The computer-readable medium of  claim 49 , wherein the eNB is configured for millimeter wave (mmWave) communication.