MCA ECC PT1 Meeting 22.-24.06.

Antenna Base station antenna down tilt Preconditions are defined in ECC Report 093 (2008/05) in chapter 6.4 Terrestrial antennas assumed in the studies Chapter 6.4.1 describes the Down Tilt Angle = 0 degrees for MCL (Minimum Coupling Loss) calculations for scenario 1 and 2 Chapter 6.4.2 describes the Down Tilt Angle = 2 degrees for SEAMCAT calculations Base station horizontal antenna pattern For MCL and SEAMCAT calculations a three sector cell with uniform gain in the horizontal plane is used (equals omni-directional within opening angle of 120 degrees in horizontal plane) Feeder Loss Defined in the ECC reports 187 as well Newer BTS/NodeB/eNodeB use more often “Remote Radio Heads” where the feeder loss is ~0dB (especially at higher frequency bands) Body Loss Description of “Human body shielding effect“ is done in chapter 9.2.2 of ECC Report 093 with application on the interference scenarios

Antenna 2 Preconditions of antenna parameters ECC Report 093 (2008/05) based on ITU-R F.1336-1 (2000/05) antenna radiation pattern ECC Report 187 (2013/01) based on ITU-R F.1336-3 (2012/03) antenna radiation pattern Latest recommended antenna radiation pattern ITU-R F.1336-4 (2014/02) with refining more real antenna pattern (especially side lobes) The 3dB beamwidth in the elevation plane is derived with the same formula (for ITU-R F.1336 – 1, -3 and -4) in case of involving sectoral antennas with a 3dB beamwidth less than about 120° in both the azimuth plane and the elevation plane! Application of three 120° sectoral antennas as in ECC report 093 is still valid but not the absolut worst case! Typical antennas used in ITU BS have a 3dB beamwidth of 90° or 65° in azimuth plane => the 3dB beamwidth in elevation gets higher (main lobe is greater) and therefore the antenna gain for the sidlobes increases too! Worsening parameters NOT taken into account Worst case angle calculation for MCL based on ITU-R F.1336-4 leads to higher antenna gain at worst case angle and therefore to higher margin in the link budget calculation Reflections on the ground plane are not takin into account anyway Typical antennas with 3dB beamwidth of 90° or 65° in azimuth plane

Real Network Handover Statistics Aircraft-based

Additional Topics User can use manual network search E.g. Users in border regions have manual mode permanently switched on. User may disable roaming

Interference - 1 Differences between the onboard UE and UE at the ground Moves with very high speed Doppler Shift Network algorithms are designed for ground UE -> Timing advance and equalization High above the surface -> LOS to cells in a big area Can receive cells in huge distances

Interference – 2 Additional load to the ground network Same signalling protocols as for UE at ground Handover Cell reselection / tracking area update Random Access Channel and MME affected Difference is the speed of the aircraft Every onboard UE will perform HO every 10s -> or cell reselection for data users Frequent Tracking Area Updates for idle mode UE

Interference – 3 Additional load to the ground network Random Access Procedure Adjacent cells use different Acess Preamble sets Onboard UE is received by distant ground eNB Some of them would have the same AP set RACH has no destination address, only AP number Phantom RACH eNB answers all RACH in its AP set range One RACH request is answered by dozens of eNB

Interference – 4 Interference to the cell where the onboard UE is connected Inter Carrier Interference (ICI) Doppler Shift Frequency offset creates interference to adjacent ressource blocks Inter SymbolInterference (ISI) Timing advance of the ground cell is designed for ground UE Due to the high speed of the aircraft theTA of onboard UE doesn‘t follow the rapid change in distance

Interference – 5 Interference to the other cells Interference avoidance by Different frequencies in adjacent cells (GSM) Different scrambling code in adjacent cells (UMTS) Far away cells Can have the same frequency / scrambling code Interference to other connections

Interference – 6 Interference canellation (IC) in uplink IC detects one or more strong interferers Known Reference Symbols (RS) Subtracts the detected interferer from the signal RS needs to be different in adjacent cells for IC Far away cells Could have the same RS IC can‘t detect these interferers Doppler shift Generates some noise to the RS IC detects wrong channel for the interferer IC subtracts wrong signal (could even make things worse)

Timer HPPLMN Timer HPPLMN Re-Connect to Home Network Examples: O2-DE: 6min, Vodafone-DE: 30min Differentiated SIM/UE world Only configurable via HomeNetwork