Evolved node-B and user equipment and methods for operation in a coverage enhancement mode

1. An Evolved Node-B (eNB) to operate in accordance with a coverage enhancement mode, the eNB comprising hardware processing circuitry to:

during a legacy sub-frame:

transmit a system information block (SIB) in legacy SIB frequency resources according to a legacy SIB transmission format; and

refrain from transmission of channel state information reference signals (CSI-RS);

during a first coverage enhancement sub-frame:

transmit a first portion of the SIB in first SIB frequency resources included in the legacy SIB frequency resources; and

transmit a first set of CSI-RS in first CSI-RS frequency resources that include least a portion of the legacy SIB frequency resources.

2. The eNB according to claim 1 , the hardware processing circuitry further to, during a second coverage enhancement sub-frame:

transmit a second portion of the SIB in second SIB frequency resources included in the legacy SIB frequency resources; and

transmit a second set of CSI-RS in second CSI-RS frequency resources that include at least a portion of the legacy SIB frequency resources,

wherein at least a portion of the first CSI-RS frequency resources are from the second CSI-RS frequency resources.

3. The eNB according to claim 1 , wherein the first SIB frequency resources are determined according to a puncturing of the legacy SIB frequency resources by the first CSI-RS frequency resources.

4. The eNB according to claim 1 , wherein the first SIB frequency resources are determined according to a rate-matching of the legacy SIB frequency resources by the first CSI-RS frequency resources.

5. The eNB according to claim 1 , wherein the first CSI-RS frequency resources are determined according to a sub-frame index of the first coverage enhancement sub-f ram e.

6. The eNB according to claim 1 , wherein the SIBS and CSI-RS are transmitted as part of one or more orthogonal frequency division multiplexing (OFDM) signals and the frequency resources are resource elements (REs) of the OFDM signals.

7. The eNB according to claim 1 , wherein:

the legacy sub-frame is a sub-frame that is designated for transmission of the SIB for reception by at least a legacy User Equipment (UE); and

the first portion of the SIB is a diversity repetition of the SIB that enables diversity reception of the SIB by a UE operating in the coverage enhancement mode.

8. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for communication in a coverage enhancement mode, the operations to configure the one or more processors to:

during a legacy sub-frame:

transmit a system information block (SIB) in legacy SIB frequency resources according to a legacy SIB transmission format; and

refrain from transmission of channel state information reference signals (CSI-RS);

during a first coverage enhancement sub-frame:

transmit a first portion of the SIB in first SIB frequency resources included in the legacy SIB frequency resources; and

transmit a first set of CSI-RS in first CSI-RS frequency resources that include least a portion of the legacy SIB frequency resources.

9. The non-transitory computer-readable storage medium according to claim 8 , the operations to further configure the one or more processors to:

during a second coverage enhancement sub-frame:

transmit a second portion of the SIB in second SIB frequency resources included in the legacy SIB frequency resources; and

transmit a second set of CSI-RS in second CSI-RS frequency resources that include at least a portion of the legacy SIB frequency resources,

wherein at least a portion of the first CSI-RS frequency resources are excluded from the second CSI-RS frequency resources.

10. The non-transitory computer-readable storage medium according to claim 8 , wherein the first SIB frequency resources are determined according to a puncturing of the legacy SIB frequency resources by the first CSI-RS frequency resources or according to a rate-matching of the legacy SIB frequency resources by the first CSI-RS frequency resources.

11. A method of communicating in a coverage enhancement mode, the method comprising:

during a legacy sub-frame:

transmitting a system information block (SIB) in legacy SIB frequency resources according to a legacy SIB transmission format; and

refraining from transmission of channel state information reference signals (CSI-RS);

during a first coverage enhancement sub-frame:

transmitting a first portion of the SIB in first SIB frequency resources included in the legacy SIB frequency resources; and

transmitting a first set of CSI-RS in first CSI-RS frequency resources that include at least a portion of the legacy SIB frequency resources.

12. The method according to claim 11 , further comprising:

during a second coverage enhancement sub-frame:

transmitting a second portion of the SIB in second SIB frequency resources included in the legacy SIB frequency resources; and

transmitting a second set of CSI-RS in second CSI-RS frequency resources that include at least a portion of the legacy SIB frequency resources,

wherein at least a portion of the first CSI-RS frequency resources are excluded from the second CSI-RS frequency resources.

13. The method according to claim 11 , wherein the first SIB frequency resources are determined according to a puncturing of the legacy SIB frequency resources by the first CSI-RS frequency resources or according to a rate-matching of the legacy SIB frequency resources by the first CSI-RS frequency resources.