System and method for random access in heterogeneous communications systems

1. A method for operating a user equipment (UE), the method comprising:

measuring, by the UE, received reference signals to generate reference signal measurements, each of the received reference signals corresponding to a different group of network element identifiers in a plurality of groups of network element identifiers;

selecting, by the UE, a set of random access channel (RACH) parameters from a plurality of sets of RACH parameters, a different one of the plurality of sets of RACH parameters being configured for each of the plurality of groups of network element identifiers, and the selected set of RACH parameters being configured for a specific group of network element identifiers that corresponds to a specific one of the received reference signals; and

performing, by the UE, a random access procedure according to the selected set of RACH parameters,

wherein performing the random access procedure according to the selected set of RACH parameters comprises:

transmitting a preamble with a transmit power level on a set of network resources in accordance with the specific received reference signal;

decoding a control channel in accordance with a second network element identifier and a third network element identifier in the specific group of network element identifiers;

decoding a data channel indicated by the decoded control channel in accordance with a fourth network element identifier and a fifth network element identifier in the specific group of network element identifiers and the specific received reference signal; and

transmitting a message in a resource allocation indicated by the decoded data channel, with reference signals modulated with a sixth network element identifier in the specific group of network element identifiers and data scrambled and encoded with a seventh network element identifier in the specific group of network element identifiers in accordance with the specific received reference signal.

2. The method of claim 1 , the specific received reference signal being associated with a first individual network element identifier in the specific group of network element identifiers.

3. The method of claim 2 , the specific received reference signal comprising a channel state information reference signal (CSI-RS) generated from a sequence based on the first network element identifier.

4. The method of claim 1 , the control channel comprising a physical downlink control channel (PDCCH), the second network element identifier is a PDCCH identifier for descrambling and decoding, and the third network element identifier is a RACH specific identifier for demodulating a demodulation reference signal (DMRS) for the PDCCH.

5. The method of claim 1 , the data channel comprising a physical downlink shared channel (PDSCH), the fourth network element identifier is a PDSCH identifier for descrambling and decoding the PDSCH, and the fifth network element identifier is a RACH specific identifier for demodulating a DMRS for the PDSCH.

6. The method of claim 1 , the message being transmitted on a physical uplink shared channel (PUSCH), the sixth network element identifier comprising a PUSCH identifier for scrambling and encoding the PUSCH, and the seventh network element identifier is a RACH specific identifier for modulating a DMRS for the PUSCH.

7. The method of claim 1 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes a different combination of network element identifiers.

8. The method of claim 1 , wherein network element identifiers in the plurality of groups of network element identifiers are configured to be used for generating pseudo-random sequences.

9. The method of claim 1 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes at least one network element identifier that is not a physical cell identifier (PCID).

10. A user equipment (UE) comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to:

measure received reference signals to generate reference signal measurements, each of the received reference signals corresponding to a different group of network element identifiers in a plurality of groups of network element identifiers;

select a set of random access channel (RACH) parameters from a plurality of sets of RACH parameters, a different one of the plurality of sets of RACH parameters being configured for each of the plurality of groups of network element identifiers, and the selected set of RACH parameters being configured for a specific group of network element identifiers that corresponds to a specific one of the received reference signals; and

perform a random access procedure according to the selected set of RACH parameters,

wherein the instructions to perform the random access procedure according to the selected set of RACH parameters include instructions to transmit a preamble with a transmit power level on a set of network resources in accordance with the specific received reference signal, to decode a control channel in accordance with a second network element identifier and a third network element identifier in the specific group of network element identifiers, to decode a data channel indicated by the decoded control channel in accordance with a fourth network element identifier and a fifth network element identifier in the specific group of network element identifiers and the specific received reference signal, and to transmit a message in a resource allocation indicated by the decoded data channel, with reference signals modulated with a sixth network element identifier in the specific group of network element identifiers and data scrambled and encoded with a seventh network element identifier in the specific group of network element identifiers in accordance with the specific received reference signal.

11. The UE of claim 10 , the specific received reference signal being associated with a first individual network element identifier in the specific group of network element identifiers.

12. The UE of claim 11 , the specific received reference signal comprising a channel state information reference signals (CSI-RS) that was generated from a sequence based on the first network element identifier.

13. The UE of claim 10 , the control channel comprising a physical downlink control channel (PDCCH), the second network element identifier is a PDCCH identifier for descrambling and decoding, and the third network element identifier is a RACH specific identifier for demodulating a demodulation reference signal (DMRS) for the PDCCH.

14. The UE of claim 10 , the data channel comprising a physical downlink shared channel (PDSCH), the fourth network element identifier is a PDSCH identifier for descrambling and decoding the PDSCH, and the fifth network element identifier is a RACH specific identifier for demodulating a DMRS for the PDSCH.

15. The UE of claim 10 , the message transmitted on a physical uplink shared channel (PUSCH), the sixth network element identifier comprises a PUSCH identifier for scrambling and encoding the PUSCH, and the seventh network element identifier is a RACH specific identifier for modulating a DMRS for the PUSCH.

16. The UE of claim 10 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes a different combination of network element identifiers.

17. The UE of claim 10 , wherein network element identifiers in the plurality of groups of network element identifiers are configured to be used for generating pseudo-random sequences.

18. The UE of claim 10 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes at least one network element identifier that is not a physical cell identifier (PCID).

19. A computer program product comprising a non-transitory computer readable storage medium storing programming, the programming including instructions to:

measure received reference signals to generate reference signal measurements, each of the received reference signals corresponding to a different group of network element identifiers in a plurality of groups of network element identifiers;

select a set of random access channel (RACH) parameters from a plurality of sets of RACH parameters, a different one of the plurality of sets of RACH parameters being configured for each of the plurality of groups of network element identifiers, and the selected set of RACH parameters being configured for a specific group of network element identifiers that corresponds to a specific one of the received reference signals; and

perform a random access procedure according to the selected set of RACH parameters,

wherein the instructions to perform the random access procedure according to the selected set of RACH parameters include instructions to transmit a preamble with a transmit power level on a set of network resources in accordance with the specific received reference signal, to decode a control channel in accordance with a second network element identifier and a third network element identifier in the specific group of network element identifiers, to decode a data channel indicated by the decoded control channel in accordance with a fourth network element identifier and a fifth network element identifier in the specific group of network element identifiers and the specific received reference signal, and to transmit a message in a resource allocation indicated by the decoded data channel, with reference signals modulated with a sixth network element identifier in the specific group of network element identifiers and data scrambled and encoded with a seventh network element identifier in the specific group of network element identifiers in accordance with the specific received reference signal.

20. The computer program product of claim 19 , the specific received reference signal being associated with a first individual network element identifier in the specific group of network element identifiers.

21. The computer program product of claim 20 , the specific received reference signal comprising a channel state information reference signal (CSI-RS) generated from a sequence based on the first network element identifier.

22. The computer program product of claim 19 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes a different combination of network element identifiers.

23. The computer program product of claim 19 , wherein network element identifiers in the plurality of groups of network element identifiers are configured to be used for generating pseudo-random sequences.

24. The computer program product of claim 19 , wherein each group of network element identifiers in the plurality of groups of network element identifiers includes at least one network element identifier that is not a physical cell identifier (PCID).

25. The computer program product of claim 19 , the data channel comprising a physical downlink shared channel (PDSCH), the fourth network element identifier is a PDSCH identifier for descrambling and decoding the PDSCH, and the fifth network element identifier is a RACH specific identifier for demodulating a DMRS for the PDSCH.

26. The computer program product of claim 19 , the message transmitted on a physical uplink shared channel (PUSCH), the sixth network element identifier comprises a PUSCH identifier for scrambling and encoding the PUSCH, and the seventh network element identifier is a RACH specific identifier for modulating a DMRS for the PUSCH.

27. The computer program product of claim 19 , the message transmitted on a physical uplink shared channel (PUSCH), the sixth network element identifier comprises a PUSCH identifier for scrambling and encoding the PUSCH, and the seventh network element identifier is a RACH specific identifier for modulating a DMRS for the PUSCH.