1. 1 以無線區域網路提供為 Last Mile 解決方案之探討 電信國家型計畫辦公室 主持人 : 鄧啟福 報告人 : 蔡志宏

2. IEEE 802.11b/a/g Outdoor WLAN 802.11b, operating at 2.4GHz, 目前最受歡迎之 WLA Ｎ標 準 Data rate : 1, 2, 5.5, 11Mbps, max. throughput approximately 4-5Mbps Taiwan’s IT industry is dominant in manufacturing 802.11b products. Outdoor WLAN Product Vendor: 數量遠少於 Indoor WLAN vendor 國內廠商 : 神遠 ( 神腦 ), 友訊, 陽慶, 中華電訊, K- Best 國外大廠 : Avaya, Cisco, ORiNOCO, etc.

3. IEEE 802.11b/a/g Outdoor WLAN 802.1la operating at 5Ghz, Providing up to 54Mbps data rate. About 22- 27 Mbps total throughput. Much smaller coverage than 802.11b AP at the same power Outdoor products are less popular than 802.11b 802.11g Operating at 2.4 Ghz Providing up to 54 Mbps data rate. About 20 Mbps + total throughput Better coverage than 802.11a AP Outdoor Products are coming soon

4. Outdoor WLAN Deployment Scenario

5. Directional Antenna and booster required at Access Point Client side outdoor unit required. More sophisticated AP and routers: security, QoS, Billing Coverage depends on Output Power (amplifier dependent, subject to regulation) Antenna gain targeted data rates channel conditions (line of sight preferred) Distance: Point-to-point: up to 5 - 20km (line of sight assumed) Point-to-Multipoint:1- 1.5 km for 512kbps – 1Mbps per user Outdoor WLAN Deployment Scenario

6. Hybrid Deployment of FTTx and WLAN Fiber to the Building(FTTB) Central Office Fiber to the Curb Remote DSLAM VDSL or SHDSL To provide effective coverage of WLAN, FTTx is suggested as the backbone behind the Access Points. In metro area, fading is more serious and user density is higher. Smaller coverage is suggested In sub-urban area, user density is lower and fading is less serious. Larger cell is suggested. Bridge/repeater

7. Public Wireless LAN Public Wireless LAN requires an Access Controller or Gateway for User Authentication: Web based vs. SIM card based. QoS control and Bandwidth Control Security and Privacy Roaming among Public WLAN and GPRS/3G is a hot area. Must cope with interferences from Bluetooth, Private/Public WLAN, Microwave oven etc.

8. Technical Issues in Spectrum Management of Public WLAN as Wireless Local Loop  Current 802.11b only allow 3 operator to coexist ;each using 1channel. However,Frequency Planning for Public WLAN may be 2-dimensional(suburban outdoor) or 3- dimensional(indoor/outdoor in metro area).  Fewer operators are better for Frequency planning.  In conflict with deregulation policy  Only 802.11a allow more channels(up to 8 channels) separated.  More mixed mode WLAN will appear  802.11b+ 802.11a  802.11g + 802.11a 8

9. Issues in Spectrum Management of Public WLAN  Most Access Point may be configured with a designated frequency channel.  When interferences is high, AP may automatic change channels.  Agreements on Frequency Planning of WLAN can easily fail, due to interferences. 1 6 11 interferences 9

10. 實施建議 因頻寬上限, 宜鼓勵 Outdoor WLAN 提供新服務 ( 如 VoIP, 雙網整合服務 ) 而非僅寬頻接取 FTTx 與 Outdoor WLAN 需結合架構方能完整 採取 ADSL+Outdoor WLAN 初步容易架設但長期頻寬 有所不足 HFC+Outdoor WLAN 架構初步可行, 長期視 HFC 品質 而定 新固網業者 Last Mile 問題可部份解決, 但長期仍需自建 FTTx 或與電路出租業者合作 室外頻率需詳細登記協調或指配新 WLAN 頻率