Transmissions of downlink control channels for low cost ues

Patent metadata

Field	Value
Publication number	US-2016270038-A1
Application number	US-201615064529-A
Country	US
Kind code	A1
Filing date	Mar 8, 2016
Priority date	Mar 11, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

Methods and apparatus are provided to support transmissions of control channels with coverage enhancements (CE) to low cost (LC) user equipments (LC/CE UEs) in a narrowband of a system bandwidth. A narrowband for a control channel transmission can depend on a type of information being scheduled for transmission by the control channel.

First claim

What is claimed is:

1 . A base station comprising:
a transmitter configured to transmit, in a first subframe and within a first narrowband that includes six consecutive resource blocks (RBs) in a downlink (DL) system bandwidth, a physical DL control channel (PDCCH), wherein:
each RB includes a number of resource elements (REs) indexed in ascending order in a frequency domain and the six consecutive RBs in the first narrowband are indexed in ascending order according to the indexes of respective REs,
when the PDCCH is transmitted over a set of two RBs, the PDCCH is mapped to a first number of control channel elements (CCEs), each CCE from the first number of CCEs includes resource elements groups (REGs) from a first RB and from a second RB, and each REG includes a number of REs either from the first RB or from the second RB,
when the PDCCH is transmitted over a set of four RBs, the PDCCH is mapped to a second number of CCEs, each CCE from the second number of CCEs includes REGs from a third RB, a fourth RB, a fifth RB, and a sixth RB, and each REG includes a number of REs either from the third RB, or from the fourth RB, or from the fifth RB, or from the sixth RB, and
when the PDCCH is transmitted over the six consecutive RBs, the PDCCH is mapped over REs first across the six consecutive RBs, starting from the RE with the lowest index, and then across symbols of the first subframe.

2 . The base station of claim 1 , wherein:
the first RB and the second RB are a first two RBs of the six consecutive RBs, and the third RB, the fourth RB, the fifth RB, and the sixth RB are a last four RBs of the six consecutive RBs.

3 . The base station of claim 1 , wherein the transmitter is further configured to transmit, in a second subframe and over a set of RBs within a second narrowband that includes six consecutive RBs, a physical downlink shared channel (PDSCH) that is mapped over REs first across the set of RBs, starting from the RE with the lowest index, and then across symbols of the second subframe.

4 . The base station of claim 1 , wherein REs used for transmission of a primary broadcast channel, or for transmission of synchronization signals, or for transmission of channel state information reference signals (CSI-RS), or for transmission of common reference signals (CRS), or for transmission of demodulation reference signals (DMRS) are not used for transmission of the PDCCH.

5 . The base station of claim 1 , wherein the transmitter is further configured to transmit signaling configuring the PDCCH transmission (i) over CCEs only in the set of two RBs or only in the set of four RBs or (ii) over REs in both the set of two RBs and the set of four RBs.

6 . A user equipment (UE) comprising:
a receiver configured to receive, in a first subframe and within a first narrowband that includes six consecutive resource blocks (RBs) in a downlink (DL) system bandwidth, a physical DL control channel (PDCCH), wherein:
each RB includes a number of resource elements (REs) indexed in ascending order in a frequency domain and the six consecutive RBs in the first narrowband are indexed in ascending order according to the indexes of respective REs,
when the PDCCH is received over a set of two RBs, the PDCCH is mapped to a first number of control channel elements (CCEs), each CCE from the first number of CCEs includes resource elements groups (REGs) from a first RB and from a second RB, and each REG includes a number of REs either from the first RB or from the second RB,
when the PDCCH is received over a set of four RBs, the PDCCH is mapped to a second number of CCEs, each CCE from the second number of CCEs includes REGs from a third RB, a fourth RB, a fifth RB, and a sixth RB, and each REG includes a number of REs either from the third RB, or from the fourth RB, or from the fifth RB, or from the sixth RB, and
when the PDCCH is received over the six consecutive RBs, the PDCCH is mapped over REs first across the six consecutive RBs, starting from the RE with the lowest index, and then across symbols of the first subframe.

7 . The UE of claim 6 , wherein:
the first RB and the second RB are a first two RBs of the six consecutive RBs, and the third RB, the fourth RB, the fifth RB, and the sixth RB are a last four RBs of the six consecutive RBs.

8 . The UE of claim 6 , wherein the receiver is further configured to receive, in a second subframe and over a set of RBs within a second narrowband that includes six consecutive RBs, a physical downlink shared channel (PDSCH) that is mapped over REs first across the set of RBs, starting from the RE with the lowest index, and then across symbols of the second subframe.

9 . The UE of claim 6 , wherein REs used for reception of a primary broadcast channel, or for reception of synchronization signals, or for reception of channel state information reference signals (CSI-RS), or for reception of common reference signals (CRS), or for reception of demodulation reference signals (DMRS) are not used for reception of the PDCCH.

10 . The UE of claim 6 , wherein the receiver is further configured to receive signaling configuring the PDCCH reception (i) over CCEs only in the set of two RBs or only in the set of four RBs or (ii) over REs in both the set of two RBs and the set of four RBs.

11 . A base station comprising:
a transmitter configured to transmit within one or more first narrowbands of six resource blocks (RBs) a physical downlink control channel (PDCCH) scheduling a transmission of a physical downlink shared channel (PDSCH) conveying one or more random access response (RAR) messages, wherein:
each RAR message is associated with a random access preamble transmission and includes scheduling information for a transmission of a physical uplink shared channel (PUSCH) in a number of transmission time intervals (TTIs), and
the scheduling information includes 20 binary elements when the PDSCH transmission and the PUSCH transmission are according to a first coverage enhancement (CE) mode and includes 12 binary elements when the PDSCH transmission and the PUSCH transmission are according to a second CE mode; and
a receiver configured to receive the PUSCH according to the scheduling information.

12 . The base station of claim 11 , wherein an information element (IE) indicating an adjustment for a PUSCH transmission power, a binary IE indicating request or no request for a channel state information report, and a binary IE indicating zero or non-zero delay for the PUSCH transmission are included in the scheduling information corresponding to the first CE level and are not included in the scheduling information corresponding to the second CE level.

13 . The base station of claim 12 , wherein:
when non-zero delay is indicated for the PUSCH transmission, the PUSCH transmission is delayed by the number of TTIs, and the number of TTIs is larger than one.

14 . The base station of claim 11 , wherein:
the scheduling information includes an information element (IE) indicating of one or more second narrowbands for a subsequent PDCCH transmission, and one state of the IE indicates the one or more first narrowbands.

15 . The base station of claim 11 , wherein the transmitter is further configured to transmit in a system information block a set of available CE levels for a random access preamble transmission and an indication for a location of the one or more first narrowbands in a downlink system bandwidth for each CE level from the set of CE levels.

16 . A user equipment comprising:
a receiver configured to receive within one or more first narrowbands of six resourc

Assignees

• Samsung Electronics Co Ltd

Inventors

• Papasakellariou Aris

Classifications

• H04W72/23 Primary

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/042 Primary

  Electricity · mapped topic

• H04L5/0053

  Allocation of signalling, i.e. of overhead other than pilot signals · CPC title

• H04W74/008

  Electricity · mapped topic

• H04L1/08 Primary

  by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} · CPC title