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Indoor Channel Measurements for TGac. Minho Cheong, ETRI. Measurement Environment (1/2). March 2009 doc.:IEEE 802.11-09/0345r0. Indoor 8x8(ULA) MIMO 100MHz channel at 5.25GHz
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Indoor Channel Measurements for TGac Minho Cheong, ETRI
Measurement Environment (1/2) March 2009 doc.:IEEE 802.11-09/0345r0 • Indoor 8x8(ULA) MIMO 100MHz channel at 5.25GHz • A mixed measurement of LOS(6,7,8,9) and NLOS(the others) • Used the channel sounder system developed by ETRI desks c concrete wall 9 8 7 6 steel wall 10m Tx Rx partition 1 2 3 4 5 10m a b Minho Cheong, ETRI
Measurement Environment (2/2) March 2009 doc.:IEEE 802.11-09/0345r0 • Tx antenna height is 2m, Rx antenna height is 1m • Two independent channel measurements at each location (Rx is rotated 90) Tx Tx Rx Rx • Parallel to Tx antenna Perpendicular to Tx antenna • (end-fire case may occur) Minho Cheong, ETRI
ETRI Channel Sounder (BECS) HPAU (High Power Amplifier Unit) BBU (Baseband Unit) RFFU (RF Front-end Unit) PSU (Power Supply) BECS System Hardware TRXU (Transceiver Unit) TIMU (Timing Unit) March 2009 doc.:IEEE 802.11-09/0345r0 Minho Cheong, ETRI
March 2009 doc.:IEEE 802.11-09/0345r0 Measurement Result: Delay Spread • NLOS locations: about80nsec rms delay spread • TGn D-NLOS: 50nsec rms delay spread • TGn E-NLOS: 100nsec rms delay spread Minho Cheong, ETRI
March 2009 doc.:IEEE 802.11-09/0345r0 Measurement Result: Antenna Correlation • Using 8-element uniform linear isotropic antenna array (/2 spacing) at Tx and Rx • In case of max. antenna separation (3.5) • LOS locations: 0.4 ~ 0.6 and NLOS locations: about 0.3 Minho Cheong, ETRI
Capacity calculation method Narrowband channel capacity Method 1 Normalization Factor is used in stead of Wideband channel capacity Average SNR( ) of 24dB is assumed where is the is channel frequency responses, is narrowband frequency bin, is the identity matrix, denotes the average SNR, and represents Hermitian transpose. Channel Capacity March 2009 doc.:IEEE 802.11-09/0345r0 Minho Cheong, ETRI
Measurement results show the capacity CDF in NLOS locations where it is bounded between TGn channel models D & E (over the 50% CDF) March 2009 doc.:IEEE 802.11-09/0345r0 Measurement Result: Capacity (1/2) Minho Cheong, ETRI
LOS measurements vs. TGn LOS Capacity revisited from previous page with B-LOS added March 2009 doc.:IEEE 802.11-09/0345r0 Measurement Result: Capacity (2/2) Minho Cheong, ETRI
Concluding Remarks (1) • The parameters of TGn channel models seems reasonable enough to cover the 8x8 measurement results in NLOS indoor office environment. • In our measurements in LOS, there is a lot of capacity degradation, which is due to waveguide/long tunnel effect by the corridor and end-fire orientation of STA • Then our measurement results don’t correspond with the TGn channel model (D & E) LOS • The LOS measurement result except but end-fire case has more similar CDF to TGn channel model B-LOS (with smaller AS) than to D and E. March 2009 doc.:IEEE 802.11-09/0345r0 Minho Cheong, ETRI
Concluding Remarks (2) • In end-fire case, the capacity can go down to almost half the capacity of i.i.d. channel. • In order to support reasonable performance also in LOS conditions, it may need to use dual-polarized antennas for 8x8 MIMO. • Other Observed Results • In LOS, capacity calculated by simulation using TGn channel • D > E > B • Random case applied to angular domain • AoD: between +/- 30 degree, AoA: between +/- 180 degree • E > D > B • Conventional AoD/AoA value picked for D-LOS may be optimal. March 2009 doc.:IEEE 802.11-09/0345r0 Minho Cheong, ETRI
Future Work For verifying the applicability of SDMA, we will perform additional measurement campaign in several environments. Measurements with the use of dual-polarized antennas for 8x8 MIMO. Measurements and analysis of the parameters of AoD and AoA affecting the SDMA performance. March 2009 doc.:IEEE 802.11-09/0345r0 Minho Cheong, ETRI