【正文】 ?Directed Connection?Limited Coverage Area2/2/2023 7成大資訊 鄭憲宗APBSSInfrastructure網(wǎng)路AP BasicServiceSetExistingWired LANDistribution SystemOtherLANsExtend Service Set2/2/2023 8成大資訊 鄭憲宗Infrastructure網(wǎng)路 (cont.)n Access Point and Mobile Stationn Distributed System Interconnect Multiple Cells via Access Points to form a single workn Extends Wireless Coverage Arean Multiple Basic Service Sets connected together form an Extended Service Setn Allow Mobile Station to access fixed resourcen Support Roaming for Mobile Stations via Access Pointn Point Coordination Function, Power Management, Time Synchronization support through Access Point2/2/2023 9成大資訊 鄭憲宗IEEE Servicesn Provides services with the following functionality: roaming within a ESS, multiple data rates in BSSs and Power Management.n The MAC protocol is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)n MAC servicesn Association servicen Authentication servicen Distribution servicen Integration servicen Deauthentication/Deassociation service2/2/2023 10成大資訊 鄭憲宗Spread Spectrum Technologyn DSSS（ Direct Sequence Spread Spectrum）n 11channelsn PNcode長度為 11bitn 展頻寬度為 11MHzn FHSS（ Frequency Hopping Spread Spectrum）n 78 hop sequencesn 頻帶範(fàn)圍為 1MHz，n 跳頻的頻率為每秒 n Infrared Rayn 發(fā)展趨勢： DHSS往高速無線區(qū)域網(wǎng)路系統(tǒng)發(fā)展，適合辦公室環(huán)境使用； FHSS會往低價網(wǎng)路應(yīng)用發(fā)展，提供 SOHO及家庭應(yīng)用、或周邊設(shè)備之無線網(wǎng)路連結(jié)。 二月 21二月 21Tuesday, February 02, 2023n 很多事情努力了未必有結(jié)果，但是不努力卻什么改變也沒有。 02 二月 20234:23:21 下午 16:23:21二月 21n 1最具挑戰(zhàn)性的挑戰(zhàn)莫過于提升自我。 2023/2/2 16:23:2116:23:2102 February 2023n 1空山新雨后，天氣晚來秋。 二月 2116:23:2116:23Feb2102Feb21n 1故人江海別，幾度隔山川。 16:23:2116:23:2116:23Tuesday, February 02, 2023n 1乍見翻疑夢，相悲各問年。 4:23:21 下午 4:23 下午 16:23:21二月 21n 楊柳散和風(fēng)，青山澹吾慮。 二月 21二月 2116:23:2116:23:21February 02, 2023n 1意志堅(jiān)強(qiáng)的人能把世界放在手中像泥塊一樣任意揉捏。 4:23:21 下午 4:23 下午 16:23:21二月 21n 沒有失敗，只有暫時停止成功！。2/2/2023 11成大資訊 鄭憲宗直接序列展頻（ DSSS）2/2/2023 12成大資訊 鄭憲宗跳頻展頻（ FHSS）2/2/2023 13成大資訊 鄭憲宗IEEE TGan The TGa is working on the high datarate extension in the 5 GHz band, project , was able to produce a new draft standard that has the support of at least 80 % of the members.n TGa is looking at a candidate for worldwide standardization! 2/2/2023 14成大資訊 鄭憲宗IEEE TGa (cont.)n The specifications of the Physical Layer enpass data rates from 6 Mbit/s up to 54 Mbit/s, with 20 MHz spacing between adjacent channels. n All implementations are required to support 6, 12 and 24 Mbit/s. Optional extensions are for 9, 18, 36, 48 and 54Mbit/s. n The multirate mechanism of the MAC protocol ensures that all devices municate with each other at the best data rate in the present channel. 2/2/2023 15成大資訊 鄭憲宗IEEE TGbn The TGb is working on the extension of the 1 and 2 Mbit/s data rates in the GHz band with and 11 Mbit/s has reached a technical promise solution to improve the coexistence and interoperability characteris