Configuration of coverage enhancement features in cellular communication networks
According to an example aspect of the present invention, there is provided a method, comprising, receiving, by a user equipment, a timing advance command from a wireless network node, wherein the timing advance command comprises a timing advance value and the user equipment is in an inactive or idle state, selecting, by the user equipment, a coverage enhancement configuration using the timing advance value and transmitting, by the user equipment, at least one message to the wireless network node using the selected coverage enhancement configuration.
1 . A user equipment (UE) operating in a 5G New Radio (NR) Frequency Range 2 (FR2) cell and in RRC_INACTIVE during a random access (RA) procedure, the UE comprising:
at least one processor; and
at least one memory comprising computer program code that, when executed by the processor, cause the apparatus to perform the following operations:
prior to initiation of the RA procedure, receiving, via System Information Block 1 (SIB1), a mapping table that associates timing-advance (TA) ranges expressed in units of Tc=0.509 nanosecond with coverage-enhancement (CE) configurations, the mapping table consisting of exactly two TA ranges: (A) TA<1100·Tc mapped to a configuration that disables spectrum shaping and (B) TA≥1100·Tc mapped to frequency-domain spectrum shaping with symmetric extension having an extension factor α=0.25;
receiving a TA command from a wireless network node, wherein the TA command is included in a random access response (Msg2) and includes a TA value expressed in Tc units while the UE is in RRC_INACTIVE state;
selecting a coverage enhancement configuration solely from the received TA value and the stored mapping table without using any path-loss estimation and without any additional per-UE signaling; and
transmitting at least one message to the wireless network node using the selected coverage enhancement configuration, wherein the at least one message is a second RA request (Msg3) comprising a radio resource control (RRC) connection request transmitted on uplink resources indicated in Msg2 using the selected frequency-domain spectrum shaping with the symmetric extension factor α=0.25 and with no time-domain repetition of Msg3.
2 . The UE of claim 1 , wherein the mapping table is delivered as Remaining Minimum System Information (RMSI) via a Physical Broadcast Channel (PBCH) transmission of System Information Block 1 (SIB1), and the UE stores the mapping table in memory prior to initiation of the random access procedure.
3 . The UE of claim 2 wherein the symmetric extension having an extension factor α=0.25″ increases a nominal Msg3 frequency-domain allocation from NtxN_{tx}Ntx resource blocks to (1+0.25)·Ntx(1+0.25)\cdot N_{tx}(1+0.25)·Ntx resource blocks, and Msg3 is transmitted in a single uplink slot without any time-domain repetition.
4 . The UE of claim 3 , wherein the selection of the coverage-enhancement configuration is performed without using any path-loss estimate and further disregards any PRACH preamble-to-path-loss association signaled in any SIBx message.
5 . The UE of claim 4 , wherein the UE applies the selected coverage-enhancement configuration solely based on the TA value and the stored mapping table without requiring any CE-specific field in the random access response (Msg2) other than the timing advance value and an uplink grant, thereby operating with an unmodified Msg2 format.
6 . The UE of claim 5 , wherein the UE applies the selected frequency-domain spectrum shaping with the extension factor α=0.25 only to the second random access request (Msg3) and refrains from applying any spectrum shaping or repetition to subsequent uplink transmissions prior to contention resolution.
7 . The UE of claim 6 , further comprising receiving, after transmitting Msg3, a contention-resolution message of the random access procedure from the wireless network node.
8 . A system comprising:
a user equipment (UE) operating in a 5G New Radio (NR) Frequency Range 2 (FR2) cell and in RRC_INACTIVE during a random access (RA) procedure:
at least one processor; and
at least one memory comprising computer program code that, when executed by the processor, cause the apparatus to perform the following operations:
prior to initiation of the RA procedure, receiving, via System Information Block 1 (SIB1), a mapping table that associates timing-advance (TA) ranges expressed in units of Tc=0.509 nanosecond with coverage-enhancement (CE) configurations, the mapping table consisting of exactly two TA ranges: (A) TA<1100·Tc mapped to a configuration that disables spectrum shaping and (B) TA≥1100·Tc mapped to frequency-domain spectrum shaping with symmetric extension having an extension factor α=0.25;
receiving a TA command from a wireless network node, wherein the TA command is included in a random access response (Msg2) and includes a TA value expressed in Tc units while the UE is in RRC_INACTIVE state;
selecting a coverage enhancement configuration solely from the received TA value and the stored mapping table without using any path-loss estimation and without any additional per-UE signaling; and
transmitting at least one message to the wireless network node using the selected coverage enhancement configuration, wherein the at least one message is a second RA request (Msg3) comprising a radio resource control (RRC) connection request transmitted on uplink resources indicated in Msg2 using the selected frequency-domain spectrum shaping with the symmetric extension factor α=0.25 and with no time-domain repetition of Msg3.
9 . The system of claim 8 , wherein the mapping table is delivered as Remaining Minimum System Information (RMSI) via a Physical Broadcast Channel (PBCH) transmission of System Information Block 1 (SIB1), and the UE stores the mapping table in memory prior to initiation of the random access procedure.
10 . The system of claim 9 wherein the symmetric extension having an extension factor α=0.25″ increases a nominal Msg3 frequency-domain allocation from NtxN_{tx}Ntx resource blocks to (1+0.25)·Ntx (1+0.25)\cdot N_{tx}(1+0.25)·Ntx resource blocks, and Msg3 is transmitted in a single uplink slot without any time-domain repetition.
11 . The system of claim 10 , wherein the selection of the coverage-enhancement configuration is performed without using any path-loss estimate and further disregards any PRACH preamble-to-path-loss association signaled in any SIBx message.
12 . The system of claim 11 , wherein the UE applies the selected coverage-enhancement configuration solely based on the TA value and the stored mapping table without requiring any CE-specific field in the random access response (Msg2) other than the timing advance value and an uplink grant, thereby operating with an unmodified Msg2 format.
13 . The system of claim 12 , wherein the UE applies the selected frequency-domain spectrum shaping with the extension factor α=0.25 only to the second random access request (Msg3) and refrains from applying any spectrum shaping or repetition to subsequent uplink transmissions prior to contention resolution.
14 . The system of claim 13 , further comprising receiving, after transmitting Msg3, a contention-resolution message of the random access procedure from the wireless network node.
15 . A method performed by a user equipment (UE) operating in a 5G New Radio (NR) Frequency Range 2 (FR2) cell and in RRC_INACTIVE during a random access (RA) procedure, the method comprising:
prior to initiation of the RA procedure, receiving, via System Information Block 1 (SIB1), a mapping table that associates timing-advance (TA) ranges expressed in units of Tc=0.509 nanosecond with coverage-enhancement (CE) configurations, the mapping table consisting of exactly two TA ranges: (A) TA<1100·Tc mapped to a configuration that disables spectrum shaping and (B) TA≥1100·Tc mapped to frequency-domain spectrum shaping with symmetric extension having an extension factor α=0.25;
receiving a TA command from a wireless network node, wherein the TA command is included in a random access response (Msg2) and includes a TA value expressed in Tc units while the UE is in RRC_INACTIVE state;
selecting a coverage enhancement configuration solely from the received TA value and the stored mapping table without using any path-loss estimation and without any additional per-UE signaling; and
transmitting at least one message to the wireless network node using the selected coverage enhancement configuration, wherein the at least one message is a second RA request (Msg3) comprising a radio resource control (RRC) connection request transmitted on uplink resources indicated in Msg2 using the selected frequency-domain spectrum shaping with the symmetric extension factor α=0.25 and with no time-domain repetition of Msg3.
16 . The method of claim 15 , wherein the mapping table is delivered as Remaining Minimum System Information (RMSI) via a Physical Broadcast Channel (PBCH) transmission of System Information Block 1 (SIB1), and the UE stores the mapping table in memory prior to initiation of the random access procedure.
17 . The method of claim 16 wherein the symmetric extension having an extension factor α=0.25″ increases a nominal Msg3 frequency-domain allocation from NtxN_{tx}Ntx resource blocks to (1+0.25)·Ntx(1+0.25)\cdot N_{tx}(1+0.25)·Ntx resource blocks, and Msg3 is transmitted in a single uplink slot without any time-domain repetition.
18 . The method of claim 17 , wherein the selection of the coverage-enhancement configuration is performed without using any path-loss estimate and further disregards any PRACH preamble-to-path-loss association signaled in any SIBx message.
19 . The method of claim 18 , wherein the UE applies the selected coverage-enhancement configuration solely based on the TA value and the stored mapping table without requiring any CE-specific field in the random access response (Msg2) other than the timing advance value and an uplink grant, thereby operating with an unmodified Msg2 format.
20 . The method of claim 19 , wherein the UE applies the selected frequency-domain spectrum shaping with the extension factor α=0.25 only to the second random access request (Msg3) and refrains from applying any spectrum shaping or repetition to subsequent uplink transmissions prior to contention resolution.