Terminal, base station, communication system, and communication method

A base station which communicates with a user equipment (UE) in a cell, the base station comprising:

• a processor;
• a memory in electronic communication with the processor;
• instructions stored in the memory, the instructions being executable to generate a cell-specific reference signal and a demodulation reference signal, the demodulation reference signal including a first demodulation reference signal and a second demodulation reference signal;
• and
• a transmitter which transmits, to the UE, a physical control channel, the physical control channel including a first physical control channel and a second physical control channel, wherein
• the first physical control channel is a physical control channel with CRC scrambled by P-RNTI which is an identifier for paging, the instructions being executable to map the first physical control channel on common search space,
• the second physical control channel is a physical control channel with CRC corresponding to C-RNTI which is an identifier specific to the UE, the instructions being executable to map the second physical control channel on UE-specific search space, and
• the instructions are executable to:
• determine whether to generate the first demodulation reference signal or the second demodulation reference signal according to whether the physical control channel mapped on the common search space or the UE-specific search space is detected
• generate, in a case that the physical control channel mapped on the common search space is detected, the first demodulation reference signal using a sequence which is initialized based on a cell identity of the cell;
• and
• generate, in a case that the physical control channel is-mapped on UE-specific search space is detected, the second demodulation reference signal using a sequence which is initialized based on a value configured via dedicated RRC signaling,
• the transmitter transmits the first demodulation reference signal and the first physical control channel on a same antenna port(s),
• the transmitter transmits the second demodulation reference signal and the second physical control channel on a same antenna port(s),
• a resource block set for the first physical control channel consists of a pre-determined set of resource blocks included in a given bandwidth and includes the common search space, and
• a resource block set for the second physical control channel (i) consists of a set of resource blocks which are configured via dedicated RRC signaling and (ii) includes the UE-specific search space.

A communication method for use in a user equipment (UE) which communicates with a base station in a cell, the communication method comprising:

• receiving a cell-specific reference signal;
• receiving a demodulation reference signal, the demodulation reference signal including a first demodulation reference signal and a second demodulation reference signal;
• monitoring a physical control channel, the physical control channel including a first physical control channel and second physical control channel, wherein
• the first physical control channel is a physical control channel with CRC scrambled by P-RNTI which is an identifier for paging, the first physical control channel being mapped on common search space,
• the second physical control channel is a physical control channel with CRC corresponding to C-RNTI which is an identifier specific to the UE, the second physical control channel being mapped on UE-specific search space,
• the first demodulation reference signal and the first physical control channel are transmitted on a same antenna port(s),
• the second demodulation reference signal and the second physical control channel are transmitted on a same antenna port(s);
• determining whether to set the first demodulation reference signal or the second demodulation reference signal according to whether the physical control channel mapped on the common search space or the UE-specific search space is detected,
• setting, in a case that the physical control channel mapped on the common search space is detected, the first demodulation reference signal to be a signal generated using a sequence which is initialized based on a cell identity of the cell;
• and
• setting, in a case that the physical control channel mapped on the UE-specific search space is detected, the second demodulation reference signal to be a signal generated using a sequence which is initialized based on a value configured via dedicated RRC signaling, wherein
• a resource block set for the first physical control channel consists of a pre-determined set of resource blocks included in a given bandwidth and includes the common search space, and
• a resource block set for the second physical control channel (i) consists of a set of resource blocks which are configured via dedicated RRC signaling and (ii) includes the UE-specific search space.

A communication method for use in a base station which communicates with a user equipment (UE) in a cell, the communication method comprising:

• generating a cell-specific reference signal;
• generating a demodulation reference signal, the demodulation reference signal including a first demodulation reference signal and a second demodulation reference signal;
• transmitting, to the UE, a physical control channel, the physical control channel including a first physical control channel and a second physical control channel, wherein
• the first physical control channel is a physical control channel with CRC scrambled by P-RNTI which is an identifier for paging, the instructions being executable to map the first physical control channel on common search space,
• the second physical control channel is a physical control channel with CRC corresponding to C-RNTI which is an identifier specific to the UE, the instructions being executable to map the second physical control channel on UE-specific search space;
• determining whether to generate the first demodulation reference signal or the second demodulation reference signal according to whether the physical control channel mapped on the common search space or the UE-specific search space is detected,
• generating, in case that the physical control channel mapped on the common search space is detected, the first demodulation reference signal using a sequence which is initialized based on a cell identity of the cell;
• and
• generating, in a case that the physical control channel mapped on the UE-specific search space is detected, the second demodulation reference signal using a sequence which is initialized based on a value configured via dedicated RRC signaling, wherein
• the first demodulation reference signal and the first physical control channel are transmitted on a same antenna port(s),
• the second demodulation reference signal and the second physical control channel are transmitted on a same antenna port(s),
• a resource block set for the first physical control channel consists of a pre-determined set of resource blocks included in a given bandwidth and includes the common search space, and
• a resource block set for the second physical control channel (i) consists of a set of resource blocks which are configured via dedicated RRC signaling and (ii) includes the UE-specific search space.