Method and apparatus for scheduling communication for low capability devices
Methods and apparatus are described for a User Equipment (UE) with reduced processing capabilities (e.g., Machine Type Communication (MTC) UE) to transmit and receive signaling are provided. The Downlink Control Information (DCI) formats scheduling a transmission of a Physical Uplink Shared CHannel (PUSCH) or a reception of a Physical Downlink Shared CHannel (PDSCH) are designed and have a smaller size than respective DCI formats for conventional UEs. DCI formats scheduling PUSCHs to or PDSCHs for a group of MTC UEs are also designed and can have a same size as DCI formats scheduling PUSCH or PDSCH for an individual MTC UE.
1. A method for a base station, the method comprising:
identifying a first user equipment (UE) associated with a first UE class and a second UE associated with a second UE class;
generating a first downlink control information (DCI) to schedule the first UE to transmit a first physical uplink shared channel (PUSCH), wherein the first DCI comprises a first set of information elements (IEs) including a cyclic shift (CS) and orthogonal covering code (OCC) IE indicating transmission parameters for a reference signal in the first PUSCH;
generating a second DCI to schedule the second UE to transmit a second PUSCH, wherein the second DCI comprises a second set of IEs and omits a CS and OCC IE, and the second UE class is configured to bandwidth-limited low complexity UEs; and
transmitting the first DCI for the first UE and the second DCI for the second UE on a physical downlink control channel.
2. The method of claim 1 , wherein the value of CS and the value of the OCC for a reference signal transmission in the second PUSCH are predetermined in a system operation to be 0 and {1, 1}, respectively.
3. The method of claim 1 ,
wherein the first DCI is associated with synchronous hybrid automatic repeat request (HARQ) data retransmissions and does not include a HARQ process number IE, and
wherein the second DCI is associated with asynchronous HARQ data retransmissions and includes a HARQ process number IE.
4. The method of claim 1 ,
wherein the first set of IEs includes a frequency hopping (FH) IE represented by one bit and indicates whether or not a transmission of the first PUSCH is at a same part of a bandwidth or at different parts of a bandwidth during a transmission time interval,
wherein the second set of IEs does not include a FH IE, and
wherein higher layer signaling configures whether or not a transmission of the second PUSCH is at a same part of a bandwidth or at different parts of a bandwidth during a transmission time interval.
5. The method of claim 1 ,
wherein the first set of IEs includes a modulation and coding scheme (MCS) and redundancy version (RV) IE represented by a first number of bits,
wherein the second set of IEs includes a MCS IE represented by a second number of bits and does not include RV information, and
wherein the second number of bits is smaller than the first number of bits.
6. The method of claim 1 ,
wherein the first set of IEs includes a resource allocation (RA) IE represented by a first number of bits and allocates resource blocks (RBs) for a transmission of the first PUSCH over a first bandwidth,
wherein the second set of IEs includes a RA IE represented by a second number of bits and allocates RBs for a transmission of the second PUSCH over a second bandwidth,
wherein the second number of bits is smaller than the first number of bits and wherein the second bandwidth is smaller than the first bandwidth,
wherein the RA IE included in the first set of IEs indicates a transmission bandwidth with granularity of one resource block (RB), and
wherein the RA IE included in the second set of IEs indicates a transmission bandwidth with granularity of a fraction of a RB.
7. An apparatus in a base station, the apparatus comprising:
a transceiver; and
a processor configured to:
identify a first user equipment (UE) associated with a first UE class and a second UE associated with a second UE class,
generate a first downlink control information (DCI) to schedule the first UE to transmit a first physical uplink shared channel (PUSCH), wherein the first DCI comprises a first set of information elements (IEs) including a cyclic shift (CS) and orthogonal covering code (OCC) IE indicating transmission parameters for a reference signal in the first PUSCH, and
generate a second DCI to schedule the second UE to transmit a second PUSCH, wherein the second DCI comprises a second set of IEs and omits a CS and OCC IE, and the second UE class is configured to bandwidth-limited low complexity UEs, and
control the transceiver to transmit the first DCI for the first UE and the second DCI for the second UE on a physical downlink control channel.
8. The apparatus of claim 7 , wherein the value of CS and the value of the OCC for a reference signal transmission in the second PUSCH are predetermined in a system operation to be 0 and {1, 1}, respectively.
9. The apparatus of claim 7 ,
wherein the first DCI is associated with synchronous hybrid automatic repeat request (HARQ) data retransmissions and does not include a HARQ process number IE, and
wherein the second DCI is associated with asynchronous HARQ data retransmissions and includes a HARQ process number IE.
10. The apparatus of claim 7 ,
wherein the first set of IEs includes a frequency hopping (FH) IE represented by one bit and indicates whether or not the first PUSCH is at a same part of a bandwidth or at different parts of a bandwidth during a transmission time interval,
wherein the second set of IEs does not include a FH IE, and
wherein higher layer signaling configures whether or not the second PUSCH is at a same part of a bandwidth or at different parts of a bandwidth during a transmission time interval.
11. The apparatus of claim 7 ,
wherein the first set of IEs includes a modulation and coding scheme (MCS) and redundancy version (RV) IE represented by a first number of bits,
wherein the second set of IEs includes a MCS IE represented by a second number of bits and does not include RV information, and
wherein the second number of bits is smaller than the first number of bits.
12. The apparatus of claim 7 ,
wherein the first set of IEs includes a resource allocation (RA) IE represented by a first number of bits and allocates resource blocks (RBs) for the first PUSCH over a first bandwidth,
wherein the second set of IEs includes a RA IE represented by a second number of bits and allocates RBs for a transmission of the second PUSCH over a second bandwidth,
wherein the second number of bits is smaller than the first number of bits and wherein the second bandwidth is smaller than the first DCI bandwidth,
wherein the RA IE included in the first set of IEs indicates a transmission bandwidth with granularity of one resource block (RB), and
wherein the RA IE included in the second set of IEs indicates a transmission bandwidth with granularity of a fraction of a RB.