Method of transmitting and receiving device-to-device discovery signal

Abstract

A method to transmit and receive a device-to-device (D2D) discovery signal method is disclosed. The D2D discovery signal method operates using currently defined discovery signals as well as novel discovery signals, such as discovery signals employing a PUCCH-based uplink signal, an SRS-based demodulation and reference signal, or a single tone-based beacon signal. Under the D2D discovery signal method, an enhanced base station (eNB) configures the D2D discovery signal to both the transmitter (TX) user equipment (UE) and the receiver (RX) UE, then activates the D2D discovery signal to the TX and RX UEs, such that D2D signal transmission can thereafter occur from either the eNB or the TX UE, and monitored by the RX UE. Once the eNB deactivates the D2D discovery signal, D2D transmissions between UEs cease. Transmissions to configure, activate, and deactivate the D2D discovery signal can be unicast, multicast, or broadcast.

We claim: 
     
         1 . A method comprising:
 configuring, by an enhanced base station (eNB), a device-to-device (D2D) discovery signal, by:
 transmitting a first configuring signal to a first user equipment (UE), wherein the first UE is to be a transmitter of D2D transmissions; 
 transmitting a second configuring signal to a second UE, wherein the second UE is to be a monitor of D2D transmissions; 
   activating, by the eNB, D2D signaling, by:
 transmitting a first activation signal to the first UE; and 
 transmitting a second activation signal to the second UE; 
   
       wherein the first UE performs a D2D transmission to the second UE without involvement of the eNB. 
     
     
         2 . The method of  claim 1 , further comprising:
 deactivating, by the eNB, D2D signaling, by:
 transmitting a first deactivation signal to the first UE; and 
 transmitting a second deactivation signal to the second UE; 
   
       wherein D2D transmissions between the first UE and the second UE cease. 
     
     
         3 . The method of  claim 1 , configuring, by the eNB, the D2D discovery signal further comprising:
 configuring a radio network temporary identifiers (RNTI) to the first UE; and   configuring a second RNTI to the second UE.   
     
     
         4 . The method of  claim 3 , further comprising:
 configuring the RNTI to the first UE for periodicity, offset, resource, and used sequence; and   configuring the second RNTI to the second UE for periodicity, offset, resource, and used sequence.   
     
     
         5 . The method of  claim 1 , activating, by the eNB, the D2D discovery signal further comprising:
 sending, by the eNB, a downlink control information (DCI) using a physical dedicated control channel (PDCCH) to the first UE and to the second UE, wherein the DCI:
 contains one or multiple radio network temporary identifiers (RNTIs) and a cyclic redundancy check (CRC) of the DCI is masked by a first RNTI, the first RNTI comprising UEs selected as transmitters of D2D signaling; and 
 conveys a second RNTI comprising UEs selected as transmitters and monitors of D2D signaling. 
   
     
     
         6 . The method of  claim 1 , activating, by the eNB, the D2D discovery signal further comprising:
 sending, by the eNB, an activation medium access control (MAC) control element.   
     
     
         7 . The method of  claim 1 , activating, by the eNB, the D2D discovery signal further comprising:
 sending, by the eNB, an activation radio resource control (RRC) signaling.   
     
     
         8 . The method of  claim 3 , further comprising:
 configuring a cell-RNTI (C-RNTI) to the first UE; and   configuring a second C-RNTI to the second UE.   
     
     
         9 . The method of  claim 3 , further comprising:
 configuring a D2D-RNTI (D-RNTI) to the first UE; and   configuring a second D-RNTI to the second UE.   
     
     
         10 . The method of  claim 3 , further comprising:
 configuring a cell-RNTI (C-RNTI) to the first UE; and   configuring a D2D-RNTI (D-RNTI) to the second UE.   
     
     
         11 . The method of  claim 3 , further comprising:
 configuring a D2D-RNTI (D-RNTI) to the first UE; and   configuring a cell-RNTI (C-RNTI) to the second UE.   
     
     
         12 . An enhanced base station (eNB) comprising:
 an antenna;   a front end coupled to the antenna; and   logic to:
 transmit a first configuring signal to a first user equipment (UE), wherein the first UE is to be a transmitter of device-to-device (D2D) transmissions; 
 transmit a second configuring signal to a second UE, wherein the second UE is to be a monitor of the D2D transmissions; 
 transmit a first activation signal to the first UE; and 
 transmit a second activation signal to the second UE; 
   
       wherein succeeding D2D transmissions between the first UE and the second UE take place without involvement of the eNB. 
     
     
         13 . The eNB of  claim 12 , wherein the logic further:
 transmits a first deactivation signal to the first UE; and   transmits a second deactivation signal to the second UE;   
       wherein D2D transmissions between the first UE and the second UE cease. 
     
     
         14 . The eNB of  claim 12 , wherein the logic comprises a software program executed by a central processing unit in the eNB. 
     
     
         15 . The eNB of  claim 12 , wherein the logic comprises an application-specific integrated circuit driving a state machine implemented using logic registers. 
     
     
         16 . A user equipment (UE) comprising:
 an antenna;   a front end coupled to the antenna; and   logic to:
 receive a first configuring signal from an enhanced base station (eNB), wherein the configuration signal indicates that the UE is to be a transmitter of device-to-device (D2D) transmissions; 
 receive a second configuring signal, wherein the second configuration signal indicates that a second UE is to be a monitor of the D2D transmissions; 
 receive a first activation signal from the eNB; 
   
       wherein the UE is thereafter capable of sending D2D transmissions to the second UE without further involvement of the eNB. 
     
     
         17 . The UE of  claim 16 , wherein the logic further:
 receives a deactivation signal from the eNB;   
       wherein D2D transmissions between the first UE and the second UE cease. 
     
     
         18 . The UE of  claim 16 , wherein the logic comprises a software program executed by a central processing unit in the UE. 
     
     
         19 . The UE of  claim 16 , wherein the logic comprises an application-specific integrated circuit driving a state machine implemented using logic registers.