Method and apparatus for random access on a wireless communication network
A set of reference signals can be received. Each of the set of reference signals can be periodically transmitted by a network entity. Information of a plurality of random access channel preambles and a plurality of reference signals from the set of reference signals can be received via a dedicated radio resource control message. At least one reference signal of the plurality of reference signals can be detected. A reference signal can be selected from the detected at least one reference signal. A random access channel preamble of the plurality of random access channel preambles can be transmitted in a contention-free random access procedure. The random access channel preamble for transmission can be determined based on the selected reference signal.
1. A method at a user equipment, the method comprising:
receiving, at the user equipment, a set of reference signals, where each of the set of reference signals is periodically transmitted by a network entity;
receiving, via a dedicated radio resource control message, information of a plurality of random access channel preambles and a plurality of reference signals from the set of reference signals;
detecting at least one reference signal of the plurality of reference signals;
selecting a reference signal from the detected at least one reference signal; and
transmitting a random access channel preamble of the plurality of random access channel preambles in a contention-free random access procedure, where the random access channel preamble for transmission is determined based on the selected reference signal.
2. The method according to claim 1 , wherein the method further comprises:
identifying a plurality of random access channel resources associated with the selected reference signal;
selecting a random access channel resource from the plurality of random access channel resources; and
transmitting the random access channel preamble on the random access channel resource.
3. The method according to claim 2 , wherein the random access channel resource is a time and frequency random access channel resource.
4. The method according to claim 1 ,
wherein the information includes association information of each of the plurality of random access channel preambles with each of the plurality of reference signals, and
wherein the random access channel preamble for transmission is determined based on the selected reference signal and the received association information.
5. The method according to claim 1 , wherein the plurality of reference signals comprises a plurality of synchronization signal blocks, where a synchronization signal block of the plurality of synchronization signal blocks comprises at least one synchronization signal.
6. The method according to claim 1 ,
wherein the plurality of reference signals comprises a plurality of channel state information reference signals, and
wherein the method further comprises:
receiving configuration information of a plurality of channel state information reference signal resources; and
receiving the plurality of channel state information reference signals on the plurality of channel state information reference signal resources.
7. The method according to claim 1 , wherein the plurality of reference signals comprises at least one synchronization signal block and at least one channel state information reference signal.
8. The method according to claim 1 , further comprising monitoring a control channel search space based on the selected reference signal in response to transmitting the random access channel preamble.
9. The method according to claim 1 , further comprising receiving at least a physical downlink shared channel as a response to the transmitted random access channel preamble, wherein the random access channel preamble is transmitted on a random access channel resource.
10. The method according to claim 9 , further comprising determining a random access radio network temporary identifier based on the random access channel resource, wherein receiving at least the physical downlink shared channel is based on the selected reference signal and based on the determined random access radio network temporary identifier.
11. The method according to claim 1 , further comprising:
receiving a broadcast channel associated with the selected reference signal; and
obtaining timing information from the broadcast channel, wherein the timing information comprises at least one of symbol-level timing information, slot-level timing information, and frame-level timing information.
12. The method according to claim 11 , wherein the broadcast channel further comprises information of a transmission pattern of the set of reference signals.
13. The method according to claim 1 , wherein the set of reference signals is periodically transmitted with a common periodicity.
14. The method according to claim 1 , further comprising performing mobility measurements on the set of reference signals.
15. An apparatus comprising:
a transceiver that
receives a set of reference signals, where each of the set of reference signals is periodically transmitted by a network entity, and
receives, via a dedicated radio resource control message, information of a plurality of random access channel preambles and a plurality of reference signals from the set of reference signals; and
a controller coupled to the transceiver, where the controller
detects at least one reference signal of the plurality of reference signals, and
selects a reference signal from the detected at least one reference signal,
wherein the transceiver transmits a random access channel preamble of the plurality of random access channel preambles in a contention-free random access procedure, where the random access channel preamble for transmission is determined based on the selected reference signal.
16. The apparatus according to claim 15 ,
wherein the controller
identifies a plurality of random access channel resources associated with the selected reference signal, and
selects a random access channel resource from the plurality of random access channel resources, and
wherein the transceiver transmits the random access channel preamble on the random access channel resource.
17. The apparatus according to claim 15 ,
wherein the information includes association information of each of the plurality of random access channel preambles with each of the plurality of reference signals, and
wherein the random access channel preamble for transmission is determined based on the selected reference signal and the received association information.
18. The apparatus according to claim 15 , wherein the plurality of reference signals comprises a plurality of synchronization signal blocks, where a synchronization signal block of the plurality of synchronization signal blocks comprises at least one synchronization signal.
19. The apparatus according to claim 15 ,
wherein the plurality of reference signals comprises a plurality of channel state information reference signals, and
wherein the transceiver
receives configuration information of a plurality of channel state information reference signal resources, and
receives the plurality of channel state information reference signals on the plurality of channel state information reference signal resources.
20. The apparatus according to claim 15 , wherein the plurality of reference signals comprises at least one synchronization signal block and at least one channel state information reference signal.