Max EIRP below 921 MHz for GSM-R and LTE-R BS 28/11/2017
Objective: ensure coexistence with MFCN BS receiving below 915 MHz Criterion used: MFCN BS blocking level + duplexer additional filtering 2
Max EIRP for an LTE carrier Conclusion of ANFR s studies 2x5 MHz in 920-925 MHz: 59 dbm 2x1.4 MHz in 919.7-921.1 MHz: 43 dbm 2x3 MHz in 918-921 MHz: 22 dbm 3
Max EIRP for a GSM-R carrier Conclusion of ANFR s studies 60 50 40 dbm 30 20 10 0 918.0 918.5 919.0 919.5 920.0 920.5 921.0 MHz 4
What 3GPP says
What 3GPP says Blocking level D = 0,8 db UMTS narrowband GMSK signal Additional filtering of the duplexer MCL = PL + 2 G tilt - G Rail - G MFCN Output power limitation for a GSM-R BS transmitting in 918-921 MHz 6
3GPP formula GSM-R BS max EIRP at 919,8 MHz = 39 dbm Max_output_power = Blocking_level_@918MHz + Duplexer + MCL Max_EIRP = Blocking_level_@918MHz + Duplexer + MCL + G Rail f MHz 918,2 919,8 (x2) 921 Max output power to protect GSM Max output power to protect UMTS/LTE 26,6 dbm 36,2 dbm 43,4 dbm 8,3 dbm 25,9 dbm 39,1 dbm Max EIRP (x1) 21,3 dbm 38,9 dbm 52,1 dbm (x1) The antenna gain (13 dbi as per 3GPP) is added to the more constraining output power (x2) 919,8 = (921,2-0,1) - 1,4 + 0,1 (the lowest R-GSM carrier is at 921,2 MHz) 7
Questions to be answered How to calculate the max EIRP for an LTE-R BS? Which 3GPP blocking levels should be considered? Is the MCL of 67 db considered by 3GPP valid? Considerations on the duplexer filtering 8
How to calculate the max EIRP for an LTE-R BS?
How to calculate the max EIRP for an LTE-R BS? (1/2) I OOB : Interfering signal, outside of the receiver s channel I IB : I OOB equivalent co-channel interfering signal Blocking level = Max I OOB Adjacent Channel Selectivity: ACS = I OOB - I IB ACS = Max_I OOB - Max_I IB Max I OOB and Max I IB depend on the desensitization considered Max I IB and ACS depend on the receiver s channel bandwidth wanted signal ACS I OOB I IB as per ECC Report 162 10
How to calculate the max EIRP for an LTE-R BS? (2/2) victim MFCN interfering LTE-R wanted signal I IB ACS i ACSi+1 slice i slice i+1 I OOB Each 200 khz slice contributes to the blocking of the MFCN BS = + 10 log 10 0.2 = _@918 + 918 11 10 10 = 10 10 10 10 = 10 log 10 10 10 = + 10 log 10 10 10 I slice in dbm/200khz I OOB in dbm/channel as per ECC Report 162 11
Which 3GPP blocking levels should be considered?
Blocking levels considered Victim: MFCN BS receiving in 910-915 MHz 2x5 MHz LTE carrier TS 25.104 Adjacent narrowband blocking Following in-band wideband blocking Value for D = 6 db Value for D = 1 db Interferer Validity range -47 dbm -57.6 dbm GMSK 915.3 MHz -40 dbm -50.6 dbm WCDMA 920 MHz to be used for GSM-R BS TS 37.104 Adjacent narrowband blocking Following in-band wideband blocking Value for D = 6 db Value for D = 1 db Interferer Validity range -49 dbm -59.6 dbm 1 LTE RB 915.15 MHz -40 dbm -50.6 dbm WCDMA 920 MHz to be used for LTE-R BS wideband blocking level to be used above 920 MHz 13
Desensitization & Receiver characteristics In coexistence studies where MFCN is the victim system, the following desensitization values are considered: for a BS, D = 1 db or INR = -6 db for a UE, D = 3 db or INR = 0 db These values were reminded by ECC PT1 in an LS referenced PT1(12)084/SE7(12)061 and echoed in Annex 7 of ECC Report 191. For FDD operation the requirements [related to receiver characteristics] shall be met with the transmitter(s) on. See section 7.1 of TS 37.104 14
Is the MCL of 67 db valid?
Where does this MCL of 67 db come from? 3GPP TR 25.942 Carrier: 1920 MHz (cf. 8.4.4) Distance between 2 BS: 288m (cf. 10.2.1) Antenna gain: G Rail = G MFCN = 13 dbi (cf. 10.2.1) Discrimination: 2x 3 db (cf. 10.2.1) PL = 87 db MCL = 67 db At 920 MHz, a PL of 87 db corresponds to a distance of 584m between the 2 BS Neither a distance of 288m, nor a distance of 584m are relevant between 2 BS 100m is the usual separation distance between 2 BS used for BEM 16
What MCL should be considered? Best CEPT practices Carrier: 920 MHz Distance between 2 BS: 100m Typical for BEM 15% of MFCN BS are closer than 102m from a GSM-R BS in urban areas (source: ANFR s data lab) Antenna gain: G MFCN = 15 dbi G Rail = 12 dbi (including feeder and coupling losses) Discrimination: Vertical Horizontal Rail 10 db 1 db MFCN 1 db 0 db (source: ANFR s data lab) At 920 MHz, the PL is 71.8 db and the MCL is 56.8 db Antenna considered for railway BS: Kathrein 80010305V02 Typical railway antenna height in urban areas: 20m Typical MFCN antenna height in urban areas: 30m CEPT Report 30 on BEM at 800 MHz: the PL is 70.8 db and the MCL is 46.8 db with discrimination of 2x3 db and antenna gains of 15 dbi 17
Reception mask with duplexer filtering 140 120 100-49 dbm -49 dbm + 11 db/mhz -40 dbm + 11 db/mhz ACS (db) 80 60-40 dbm -49 dbm Δ = 9 db from -49 dbm to -40 dbm 40 20 0 900 905 910 915 920 925 Frequency (MHz) 18
First results and considerations on the duplexer filtering
Max EIRP for an LTE-R BS 2x5 MHz in 920-925 MHz: 54 dbm 2x1.4 MHz in 919.7-921.1 MHz: 39 dbm 2x3 MHz in 918-921 MHz: 21 dbm Duplexer filtering: 11 db/mhz 20
Max EIRP for a GSM-R BS 60 50 40 dbm 30 20 10 0 918.0 918.5 919.0 919.5 920.0 920.5 921.0 MHz Duplexer filtering: 11 db/mhz 21
Considerations on the duplexer filtering Max EIRP for a GSM-R BS at 921 MHz: 51 dbm This would mean that MFCN BS are currently interfered by GSM-R BS transmitting in 921-925 MHz at 57 dbm EIRP No interference case reported so far The Agency understands that the duplexer filtering is underestimated The duplexer filtering is thus updated to 13 db/mhz 22
Final results
Max EIRP for an LTE-R BS 2x5 MHz in 920-925 MHz: 59 dbm 2x1.4 MHz in 919.7-921.1 MHz: 43 dbm 2x1.4 MHz in 919.5-920.9 MHz: 39 dbm These EIRP provide some room for FRMCS operations. Additional studies will review these values. A further input should be presented at the next FM56 meeting. 2x3 MHz in 918-921 MHz: 22 dbm Not suitable for FRMCS high sensitivity to the exact frequency location Duplexer filtering: 13 db/mhz 24
Max EIRP for a GSM-R BS 60 50 40 dbm 30 20 10 0 918.0 918.5 919.0 919.5 920.0 920.5 921.0 MHz Duplexer filtering: 13 db/mhz 25
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Minimum decoupling and max EIRP Rx MFCN - G MFCN + G tilt = Tx Rail + G Rail - G tilt - PL MCL = Tx Rail - Rx MFCN = PL + 2 G tilt - G Rail - G MFCN Tx Rail + G Rail = Rx MFCN + MCL + G Rail PL = 32.4 + 20log 10 (f MHz ) + 20log 10 (d km ) 27