Low overhead system information acquisition for wireless communication
A method for low overhead system information acquisition (LOSIA) is disclosed. The LOSIA method includes several techniques for transmitting common channels in a next generation Radio Access Technology (xRAT). Instead of transmitting system information in a periodic, static, cell-specific, wideband manner, the transmission is triggered by user equipment in an “on demand” manner. The LOSIA method allows the network to control the overhead, bandwidth, and periodicity, as well as other characteristics. The LOSIA method employs several different techniques to trigger the information upon which the network can act, for example, by transmitting different payloads depending on the received trigger.
1. A user equipment (UE) occupying a Radio Access Network (RAN), the UE comprising:
a processor;
memory coupled to the processor, the memory comprising instructions which, when executed by the processor, cause the processor to:
initiate a cell search of the RAN to decode a set of system information (SI) comprising a system information block (SIB), the SIB to provide a physical random access channel (PRACH) configuration;
transmit the PRACH comprising a preamble/sequence in a subframe to a RAN base station transceiver, wherein the PRACH comprising the preamble/sequence, when transmitted in the subframe, indicates a request for additional SI; and
monitor for transmission of the additional SI within a window of the subframe, wherein a position and size of the window are configured in a SI information element.
2. The UE of claim 1 , the UE to further:
decode the additional SI;
wherein the UE is thereafter able to communicate with the RAN base station.
3. The UE of claim 2 , wherein the additional SI is common to all UEs operating in the RAN.
4. The UE of claim 2 , wherein the additional SI is specific to the UE relative to other UEs operating in the RAN.
5. The UE of claim 1 , the UE to further transmit the PRACH comprising the preamble/sequence by:
randomly selecting the preamble/sequence from a set of preamble/sequences.
6. A user equipment (UE) occupying a Radio Access Network (RAN), the UE comprising:
a processor;
memory coupled to the processor, the memory comprising instructions which, when executed by the processor, cause the processor to:
initiate a cell search of the RAN to decode a set of system information (SI) comprising a system information block (SIB), the SIB to provide a physical random access channel (PRACH) configuration;
transmit the PRACH comprising a preamble/sequence in a subframe to a RAN base station transceiver, wherein the PRACH comprising the preamble/sequence, when transmitted in the subframe, indicates a request for additional SI; and
monitor for transmission of the additional SI within a window of the subframe,
wherein the PRACH comprising the preamble/sequence, when transmitted in the subframe, does not indicate:
uplink synchronization;
a scheduling request; or
a radio resource control (RRC) connection setup request.
7. The UE of claim 5 , wherein the preamble/sequence transmissions trigger additional SI associated with an identifier and the identifier is selected from a group consisting of a common radio network temporary identifier (RNTI), a UE-specific RNTI, a UE-specific RNTI that has changed following contention resolution, an RNTI specific to a service/application, and an RNTI specific to a radio access technology (RAT).
8. The UE of claim 1 , wherein the preamble/sequence indicates a request to send the additional system information for a predetermined service or application.
9. The UE of claim 8 , wherein the UE identifies the association of the preamble/sequence from broadcasted SI transmissions.
10. The UE of claim 1 , wherein a position and size of the window are configured by higher layers.
11. The UE of claim 10 , wherein the higher layer configuration is via a master information block.
12. The UE of claim 10 , wherein the higher layer configuration is via the SIB or another SIB.
13. The UE of claim 10 , wherein the higher layer configuration is via dedicated radio resource control (RRC) signaling.
14. The UE of claim 1 , wherein the position and size of the window are known to the UE.
15. The UE of claim 1 , wherein the position and size of the window are configured in a SI-ResponseWindowSize information element, wherein a range of O-10 subframes is indicated.
16. A base station (BS) occupying a Radio Access Network (RAN), the BS comprising:
a processor; and
a memory coupled to the processor, the memory comprising instructions to enable the BS to:
transmit a limited set of system information (SI) in a periodic manner, the limited set of SI to enable a user equipment (UE) to acquire a physical random access channel (PRACH);
receive a preamble/sequence from the UE using the PRACH, the PRACH having been transmitted in a subframe, wherein the PRACH comprising the preamble/sequence, when transmitted in the subframe, indicates a request for additional SI; and
transmit the additional SI within a window of the subframe, wherein a position and size of the window are configured in a SI information element;
wherein the additional SI is not continuously and periodically transmitted.
17. The BS of claim 16 , wherein the additional SI is common to all UEs operating in the RAN.
18. The BS of claim 16 , wherein the additional SI is specific to the UE relative to other UEs operating in the RAN.
19. The BS of claim 16 , wherein the PRACH comprising the preamble/sequence, when transmitted in the subframe, does not indicate:
uplink synchronization;
a scheduling request; or
a radio resource control (RRC) connection setup request.
20. The BS of claim 16 , wherein the transmission of additional SI is associated with an identifier and the identifier is selected from a group consisting of a common radio network temporary identifier (RNTI), a UE-specific RNTI, a UE-specific RNTI that has changed following contention resolution, an RNTI specific to a service/application, and an RNTI specific to a radio access technology (RAT).
21. The BS of claim 16 , the memory comprising instructions to enable the BS to further:
receive a second preamble/sequence from a second UE, wherein the second preamble/sequence is identical to the preamble/sequence; and
perform a contention resolution procedure to distinguish the UE from the second UE.
22. An apparatus of a user equipment (UE), the apparatus comprising:
radio frequency circuitry coupled to one or more antennas, the antennas to receive signals transmitted over a cellular network; and
one or more processors to execute instructions, the instructions, once executed by the one or more processors, to cause the UE to:
decode a limited set of system information (SI) comprising a coarse time and frequency synchronization, a cyclic prefix length, a duplex mode, and a physical cell identifier of a cell in the cellular network;
transmit a preamble/sequence to the cell using the radio frequency circuitry and the one or more antennas, wherein the preamble/sequence is transmitted in a dedicated time/frequency resource of the cell and indicates a request for additional SI; and
monitor a transmission window of the dedicated time/frequency resource for additional SI in the cellular network; and
decode the additional SI.
23. The apparatus of claim 22 , the instructions, once executed by the one or more processors to further:
start a timer upon transmission of the preamble/sequence; and
retransmit the preamble/sequence if the additional SI has not been decoded by the UE upon expiration of the timer.