Random access in wireless communication networks

1. A method for a wireless network node, comprising:

receiving, from a wireless terminal, a second connection request message in a random access procedure, the second connection request message including an uplink reference signal sequence;

in response to receiving the second connection request message, transmitting a contention resolution message to the wireless terminal, the contention resolution message comprising a temporary identifier associated with the wireless terminal and an identifier of the uplink reference signal sequence; and

transmitting a random access response message to the wireless terminal, wherein the random access response message comprises the temporary identifier associated with the wireless terminal and a part reserved for identifying the uplink reference signal sequence.

2. A method according claim 1 , wherein all bits of the part of the random access response message reserved for identifying the uplink reference signal sequence are set as zero.

3. A method according to claim 1 , wherein the temporary identifier associated with the wireless terminal and the part reserved for identifying the uplink reference signal sequence are transmitted within an information field, wherein a size of the information field corresponds to a maximum size of the temporary identifier associated with the wireless terminal.

4. A method according to claim 1 , wherein a size of the temporary identifier is smaller than a maximum size for the temporary identifier.

5. A method according to claim 1 , wherein a size of the part reserved for identifying the uplink reference signal sequence is a maximum size for the temporary identifier subtracted by a size of the temporary identifier.

6. A method according to claim 1 , wherein the uplink reference signal sequence is a demodulation reference signal sequence.

7. A method for a wireless terminal, comprising:

selecting an uplink reference signal sequence for random access;

transmitting a second connection request message in a random access procedure, the second connection request message including the selected uplink reference signal sequence;

in response to transmitting the second connection request message, receiving a contention resolution message, the contention resolution message comprising a temporary identifier associated with the wireless terminal and an identifier of the uplink reference signal sequence; and

receiving a random access response message, wherein the random access response message comprises the temporary identifier associated with the wireless terminal and a part reserved for identifying the uplink reference signal sequence.

8. A method according to claim 7 , wherein all bits of the part of the random access response message reserved for identifying the selected uplink reference signal sequence are set as zero.

9. A method according to claim 7 , wherein the temporary identifier associated with the wireless terminal and the part reserved for identifying the selected uplink reference signal sequence are received within an information field, wherein a size of the information field corresponds to a maximum size of the temporary identifier.

10. A method according to claim 7 , wherein a size of the temporary identifier is smaller than a maximum size for the temporary identifier.

11. A method according to claim 7 , wherein a size of the part reserved for identifying the uplink reference signal sequence is a maximum size for the temporary identifier subtracted by a size of the temporary identifier.

12. An apparatus comprising:

at least one processing core, and

at least one non-transitory memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to perform:

receive, from a wireless terminal, a second connection request message in a random access procedure, the second connection request message including an uplink reference signal sequence;

transmit, in response to receiving the second connection request message, a contention resolution message to the wireless terminal, the contention resolution message comprising a temporary identifier associated with the wireless terminal and an identifier of the uplink reference signal sequence; and

transmit a random access response message to the wireless terminal, wherein the random access response message comprises the temporary identifier associated with the wireless terminal and a part reserved for identifying the uplink reference signal sequence.

13. An apparatus comprising:

at least one processing core, and

at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to perform:

select an uplink reference signal sequence for random access;

transmit a second connection request message in a random access procedure, the second connection request message including the selected uplink reference signal sequence;

receive, in response to transmitting the second connection request message, a contention resolution message, the contention resolution message comprising a temporary identifier associated with a wireless terminal and an identifier of the uplink reference signal sequence; and

receive a random access response message, wherein the random access response message comprises the temporary identifier associated with the wireless terminal and a part reserved for identifying the uplink reference signal sequence.

14. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform a method according to claim 1 .

15. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform a method according to claim 7 .