Mutipath Delay Profiles in a 5GHz band July 2003 Mutipath Delay Profiles in a 5GHz band Naoki Kita and Yasuhiko Inoue NTT {nkita,yinoue}@ansl.ntt.co.jp N.Kita, Y.Inoue, NTT

Background#1 5GHz band wireless access systems July 2003 Background#1 5GHz band wireless access systems 4.9 - 5.0 GHz, 5.030 - 5.091 GHz Technical requirements Radio Equipment Ordinance: Article 49-21 In the near future, 5.25-5.35GHz band and 5.47-5.725GHz will be assigned for wireless access services. Requirements are not specified yet. N.Kita, Y.Inoue, NTT

Background#2 Market Plans for FWA and NWA services: July 2003 Background#2 Market Plans for FWA and NWA services: A local government is planning to install a great number of base stations to cover whole region of the city. Another city plans to install 10,000 FWA devices. Many other local governments and public organizations will follow them. Group company of NTT also plans to provide wireless internet services using this system. Other companies such as SONY and Speed Net, have their plans. N.Kita, Y.Inoue, NTT

July 2003 Background#3 Japanese frequency regulations for 4.9-5.0GHz and 5.030-5.091GHz allows three kinds of systems: 20MHz channel bandwidth PHY data rates: 6, 9, 12, 18, 24, 36, 48, 54M bit/s 10MHz channel bandwidth PHY data rates: 3, 4.5, 6, 9, 12, 18, 24, 27M bit/s 5MHz channel bandwidth PHY data rates: 1.5, 2.25, 3, 4.5, 6, 9, 12, 13.5M bit/s N.Kita, Y.Inoue, NTT

Purpose of this presentation July 2003 Purpose of this presentation To evaluate if the 802.11a PHY has enough immunity for delay spread based on the results of measurements FWA and NWA services using 5GHz band wireless access systems: based on 802.11a PHY Outdoor environment Long range (up to 3Km) Performance of the 802.11a PHY can be degraded because of delay spread N.Kita, Y.Inoue, NTT

802.11a PHY 20MHz channel spacing systems: July 2003 802.11a PHY 20MHz channel spacing systems: Tolerable delay spread will be < 200 or 250[ns] 10MHz channel spacing systems: Tolerable delay spread will be < 400 or 500[ns] ? 4 [us] 0.8 [us] 1/2 clock rate GI time 8 [us] 1.6 [us] GI time N.Kita, Y.Inoue, NTT

Results of measurements July 2003 Results of measurements Scenarios FWA: Typical residential are in Tokyo NWA: Typical urban area in Tokyo N.Kita, Y.Inoue, NTT

The FWA Scenarios The Base station and subscriber stations Antenna July 2003 The FWA Scenarios The Base station and subscriber stations Antenna Antenna Base station Omni-directional antenna Antenna height = 18, 21[m] Subscriber station Omni-directional antenna Antenna height = 5, 10[m] N.Kita, Y.Inoue, NTT

The FWA Scenarios (Cont’d) July 2003 The FWA Scenarios (Cont’d) Measurement points 18 20 19 6 7 8 9 13 17 14 1 12 5 4 10 16 24 11 15 21 25 3 2 22 23 N.Kita, Y.Inoue, NTT

The FWA Scenarios (Cont’d) July 2003 The FWA Scenarios (Cont’d) Residential area in Tokyo N.Kita, Y.Inoue, NTT

The FWA Scenarios (Cont’d) July 2003 The FWA Scenarios (Cont’d) An example of delay profile -70 Antenna height: Tx; ht = 18.0[m] Rx: hr = 2.8[m] Distance between Tx and Rx modules = 250[m] Spread: 205.1[ns] -80 -90 Received level [dBm] -100 -110 -120 -130 500 (1.7[us]) 1000 (3.3[us]) 1500 (5.0[us]) 2000 (6.7[us]) N.Kita, Y.Inoue, NTT

The FWA Scenario (Cont’d) July 2003 The FWA Scenario (Cont’d) Another example of delay profile -70 Antenna height: Tx; ht = 18.0[m] Rx: hr = 2.8[m] Distance between Tx and Rx modules = 875[m] Spread: 62.505[ns] -80 -90 Received Signal Level [dBm] -100 -110 -120 -130 500 (1.7[us]) 1000 (3.3[us]) 1500 (5.0[us]) 2000 (6.7[us]) N.Kita, Y.Inoue, NTT

The FWA Scenarios (Cont’d) July 2003 The FWA Scenarios (Cont’d) Cumulative Probability 99.99 99.9 99 95 90 80 70 Cumulative probability (%) 50 30 20 10 5 ht=21m, hr=5m ht=21m, hr=10m 1 ht=18m, hr=5m 0.1 ht=18m, hr=10m 0.01 100 200 300 400 500 600 700 50 100 150 200 250 300 Delay spread [nsec] Delay spread [nsec] N.Kita, Y.Inoue, NTT

The FWA Scenarios (Cont’d) July 2003 The FWA Scenarios (Cont’d) Summary Delay Spread depends on: antenna height of the BSs and subscriber stations reflectors In FWA cases, 90% value of delay spread will be less than 200[ns]. if base station and subscriber station are appropriately installed. LOS helps to reduce the delay spread. N.Kita, Y.Inoue, NTT

The NWA Scenario Pictures from the base station’s antenna height July 2003 The NWA Scenario Ginza area Nihonbashi Area Pictures from the base station’s antenna height Pictures from the mobile station’s antenna height N.Kita, Y.Inoue, NTT

The NWA Scenarios (Cont’d) July 2003 The NWA Scenarios (Cont’d) Measured area Tx 100m 200m 300m 400m Ginza 8 Ginza 6 Dentsu SONY Map of experimental area in Tokyo - 1 (Ginza area) Tx 100m 200m 300m 400m 500m 600m Nihonbashi 1 Kyobashi 1 Nihonbashi 2 Nihonbashi 3 Map of experimental area in Tokyo - 2 (Nihonbashi area) N.Kita, Y.Inoue, NTT

The NWA Scenarios (Cont’d) July 2003 The NWA Scenarios (Cont’d) Median of the delay spread 100 200 300 400 50 500 600 700 Median of delay spread [nsec] Distance between Tx and Rx [m] Standard deviation Ginza area Nihonbashi N.Kita, Y.Inoue, NTT

The NWA Scenarios (Cont’d) July 2003 The NWA Scenarios (Cont’d) 90% value vs. median of delay spread 100 200 300 400 500 600 700 50 150 250 350 90% value of delay spread [nsec] Median of delay spread [nsec] 90% value of cumulative delay spread: 350[ns] 20MHz channel spacing systems do not have enough immunity N.Kita, Y.Inoue, NTT

The NWA Scenarios (Cont’d) July 2003 The NWA Scenarios (Cont’d) Summary 90% value of the delay spread in the NWA environments will be 350[ns]. 20MHz channel spacing systems will not be enough. 10MHz channel spacing system is desired if we hope to support this kind of services. N.Kita, Y.Inoue, NTT

Conclusion Measured delay spread (90% value): July 2003 Conclusion Measured delay spread (90% value): About 200[ns] for the FWA scenarios. If the base stations and subscriber stations are installed appropriately. If not, delay spread increases (can be 400 ~ 500[ns]). About 350[ns] for the NWA scenarios. Not tolerable for the 20MHz channel spacing systems. 802.11j should include specifications for 10MHz channel spacing systems as well as 20MHz channel spacing systems. N.Kita, Y.Inoue, NTT