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Experimental results of indoor path-loss in actual European houses. Date: 2012-03-12. Authors:. Abstract. Experimental results of indoor path-loss in actual European houses.
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Panasonic Experimental results of indoor path-loss in actual European houses Date: 2012-03-12 Authors:
Panasonic Abstract • Experimental results of indoor path-loss in actual European houses. • Suggestion of link budget value, especially for down link, for HEMS (Home Energy Management System), based on the measurement results. • Consideration of TX output power requirement
Panasonic Background • For HEMS, wireless module will be installed in home appliances and antenna gain is limited due to small form factor. • Antenna performance may be similar to ones used for wireless remote controllers. The antenna gain of remote controllers is around -11 dBi at sub-GHz carrier wavelength. • Target link budget for HEMS is not clear so far.
Panasonic Measurement conditions for path loss Test house #1 Test house #2 Top view of this house 8.00m x 9.00m Top view of this house 8.97m x 8.97m TX point (1st floor) TX point (1st floor) Two-story house + the basement Two-story house Test house #4 Test house #3 Top view of this house 14.00m x 11.00m Top view of this house 15.00m x 15.00m TX point (2nd floor) TX point (4th floor) Two-story apartment Five-story apartment Table 1. Measurement conditions
Panasonic Measurement results of path loss Worst path loss (median) in this experiment was 78dB. Fading margin is not included in this value.
Panasonic Fading margin for HEMS • In HEMS, wireless devices are basically fixed. • Robust fading margin must be considered to avoid loss packets because channel is not frequency selective[1] and some wireless devices may be in a dead-point. • More than 99.9% link availability should be guaranteed. [1]IEEE802-11-12-101/r0
Panasonic Simple study of link budget for indoor HEMS Data rate: 100kbps (MCS0, K=7) with 2 repetition This table is utilized especially for down link in which diversity techniques cannot be used due to lack of space in STAs. [2] IEEE802-11-1-1482/r4; mentioned -3dBi and -4dBi. In this document, we chose better one. [3] Martin Handforth, Asrar U. Sheikh and Majid Abdi“Static Characterization of the Indoor Mobile Radio Channel at 946MHz”, pp.955-959, vol.2, ICPU, 1993
Panasonic Simple study of reception sensitivity level In case of 100kbps mode (MCS0, 2 repetition) Ref. [4] “Digital Communications”, John G. Prokis and Masoul Salehi, McGRAW-HILL In case of BPSK, K=7 and R=1/2, BER=1x10-5 [5]IEEE802-11-11-0552/r2
Panasonic Comparison with DCN 1482r4 • Path loss and antenna gain of STA is different each other but link budgets are almost same as each other. • Target link budget for HEMS including both pure indoor case and mixed condition of indoor and outdoor case can be up to 113dB.
Panasonic TX output power consideration AP-to-STA; To meet the 113 dB link budget under a condition of -109 dBm reception sensitivity (for downlink), TX output power must be larger than +4 dBm. • Around 6dB output backoff should be considered to get better performance of OFDM. • Around 10dBm is output power limitation for devices without an external PA from the implementation point of view. • No margin for PVT variation in case of +4dBm output power level (peak power is 10dBm). • 0dBm[2] output power level can be a good candidate for HEMS. • Note: PVT variation stands for Process-Voltage-Temperature variation
Panasonic Conclusion To actualize HEMS by using TGah specification, TGah should consider following link budget, under a condition of receiver sensitivity being around -109dBm (MCS0 w/ 2 repetition) 113 dB for AP-to-STA Required TX output power shall be at least +4 dBm for AP-to-STA (MCS0 w/ 2 repetition) • To realize 0dBm output power level, MCS0 with 2 repetition technique alone is not enough. • Combination of MCS0 rep2 and additional technique must be needed to actualize HEMS.
Panasonic Straw Poll Do you agree that in addition to MCS0 rep2 other technique to improve link margin especially for downlink should to be devised and included in Spec Framework?