![[圖]](http://www.oafrica.com/uploads/2g-3g-4g.jpg)
2009/07/06 05:00:00
LTE與WiMAX 鹿死誰手？
郭文興
大家可能發現了，WiMAX的未來發展仍舊不明，而長期演進技術(LTE)則頗有後來居上之勢。那到底是LTE、還是WiMAX會變成下一代通訊標準？
回答這個問題前，我們得先釐清LTE跟WiMAX到底是什麼，以及有何異同？
技術異同
LTE是第三代行動電話伙伴計劃(3GPP)制定的一個標準。由於3GPP是行動業者組成的國際組織，因此，制定的標準多偏向行動業者的立場。LTE也不例外。
LTE的核心在於透過修改基地台跟無線網路的無線通道技術，提升無線傳輸的效率。換句話說，行動業者只要修改基地台，並使用不同標準的手機，便可以比3G更快的傳輸速度傳遞訊號。至於後端的有線網路，則不需要做太大的修改。
WiMAX則是一種無線都會區域網路，是由WiMAX論壇(WiMAX Forum)提出。讀者可將該技術想像成一個涵蓋面積達數十公里的巨大無線基地台，在該範圍內的裝置皆可透過連線至基地台的方式存取服務。
WiMAX是為解決「最後一哩」傳輸問題而生的技術，因此，不需拉滿光纖，只要在都會區架上數個WiMAX基地台，使用者即可透過WiMAX存取各項網路服務。
由於該兩技術的定位不同，優劣之處也跟著不一樣。
舉例來說，LTE除在行動用戶這塊的支援能力較佳外，由於該技術允許業者在不更換既有3G網路的後端線路的狀況下導入該技術(意味推行成本相對較低)，因此，電信業者的導入意願普遍偏高。
至於由網路業者研發的WiMAX則是在服務品質(QoS)的表現較佳，除可同時滿足不同類型的連線需求外，也較容易整合Wi-Fi技術。
鹿死誰手
以筆者於ICC 2009的走訪結果來看，市場對於WiMAX與LTE哪個技術比較可能變成下一代通訊標準這個問題，仍沒統一共識。
研究人員認為兩個標準的底層技術都是OFDM，易於整合。因此，將來極可能只需要一個射頻裝置即可連上WiMAX與LTE兩種網路服務。
對Nokia、Siemens與Vodafone等手機與電信業者來說，推行不需要更改核心網路技術的LTE，則是十分合理的事情。
至於英特爾(Intel)等核心技術偏向網路應用的廠商，以及亞洲等通訊產業的後進國家會力推WiMAX，也屬可理解的發展趨勢。
另外，也有些專家表示，決定兩技術的推行與否，往往不是技術問題，而是政治與經濟的問題。亦即每個業者與政府都有自己的算盤，會選擇對自己最有利的陣營。
舉例來說，若某國家或當地企業已在某技術中取得許多專利，當然會主推該技術，以期在未來市場佔有一席之地。
但若單從技術角度來看，WiMAX已進入了技術成熟期，接下來就看廠商的部署策略。而LTE則處於研發中前期，雖說其有急起直追的氣勢，但在金融風暴的影響下， LTE技術的成熟時間勢必會向後延遲，當然，這段時間也將是WiMAX陣營支持者喘息與卡位的最佳時機。
結論
筆者以為，WiMAX跟LTE的競爭與過去的大小錄影帶之爭不一樣，不大可能出現「贏者全拿」的局勢。理由在於該兩技術的定位與優劣不大相同，以及電信業者多是以所屬市場需求為核心考量，而不會為WiMAX而WiMAX、或者是為LTE而LTE。
在第三世界與手機覆蓋率不高的區域，電信業者確實可透過導入WiMAX技術，滿足使用者對電話、上網與電視等通訊需求。但LTE這個被視作手機上網的昇級版技術，也可能慢慢取代3G網路。
讓我們一起來看看另外一個案例--目前是由WCDMA、CDMA2000與TD-SCDMA等幾個類似的3G手機上網技術分別佔據歐、美、亞洲等市場。由此來看，取向與設計都不大相同的WiMAX與LTE，不一定非得爭個你死我活，也有機會共存。
最後，我認為WiMAX與LTE等兩技術的真正敵人與挑戰是現有技術。如WiMAX該如何與Wi-Fi整合，以提供使用者高整合性的網路服務；以及LTE該如何透過核心網路提供遠超過現有3G技術的高速頻寬。是故，與其討論誰勝誰負，不若留心觀察上述發展。
編按：作者為台灣大學電機系計算機博士，目前任教於元智大學電機系，研究領域為無線網路，有多篇論文發表於知名國際研討會與期刊。
What is GSM, EDGE, GPRS, UMTS 3G, HSDPA, HSUPA, LTE
Posted on November 23, 2012
What is GSM?
The acronym GSM is a mobile communications system and means “Global System for Mobile Communications”. GSM supports data rates of max. 14.4 kbit / s GSM is the successor system of A, B and C networks and is commercially available in Germany since 1992.
The Global System for Mobile Communications (formerly Groupe Spécial Mobile, GSM) is a standard for fully digital mobile networks, which is used mainly for telephony, but also for circuit switched and packet-switched data transmission and text messages (short messages). It is the first standard of the so-called second generation (“2G”), replacing the analog systems of the first generation (in Germany: A-line, B-grid and C-grid) and is the world’s most popular wireless standard.
What is UMTS (UMTS broadband, 3G)?
The acronym stands for UMTS “Universal Mobile Telecommunication System”. UMTS is a mobile system with speeds of max. 384 kbit / s UMTS is the successor of GSM and commercially available since 2004 in Germany.
The Universal Mobile Telecommunications System (UMTS) is a wireless standard of the third generation (3G), with significantly higher data rates (up to 21 Mbit / s HSPA +, otherwise max. 384 kbit / s) than with the wireless standard of the second generation (2G ), the GSM standard (up to 220 kbit / s in EDGE;. otherwise max is 55 kbit / s in GPRS), possible.
The ITU had UMTS selected for IMT-2000, and it is therefore one of the standards for the third generation mobile communications. Originally, the ETSI (European Telecommunications Standards Institute) had standardized UMTS, today the 3rd Generation Partnership Project (3GPP) maintains it further. The standard is constantly being expanded, for example, increased the maximum HSDPA receive data rate (downlink). For the transmit data rate comparable with HSUPA technology is available.
What is EDGE?
EDGE means “Enhanced Data Rates for GSM Evolution” and is a transmission technique in GSM networks, the transmission rate can be increased theoretically up to 220 kbit/s.
Enhanced Data Rates for GSM Evolution (EDGE) refers to a technique for increasing the data transmission rate in GSM networks by introducing an additional modulation method. GPRS with EDGE data services to E-GPRS (Enhanced GPRS) and HSCSD be extended to ECSD.
EDGE represents an evolution of the GSM technology represents It is basically a GSM with more bits per baud. [1] EDGE with moderate effort can be integrated into mobile networks as it does not disturb the already existing mobile telephony. Essentially, it is necessary to update the software of the GSM base station and optionally to replace individual components.
What is GPRS?
GPRS is “General Packet Radio Service” and is a service between UMTS and GSM networks of permanent connection to devices sustains and transmits data packets only when necessary.
General Packet Radio Service (GPRS) (German: “General packet radio service”), the name given to the packet-based service for data transmission in GSM networks.
If GPRS is activated, only virtually, there is a permanent connection to the remote site (the so-called always-on mode). Only when real data is transmitted, the radio room is occupied, otherwise it is free for other users. Therefore, no permanent radio channel needs (as with CSD) reserved for a user to be. GPRS bills are therefore mainly dependent on the quantity of data transferred rather than connect time. However, this is also dependent on the particular contract terms with the operator.
Unlike the circuit-switched (English circuit switched) CSD data service GPRS is packet-oriented. That is, the data are converted at the transmitter into individual packets, transmitted as such, and the receiver re-assembled.
![[圖]](http://www.4gltemall.com/blog/wp-content/uploads/2012/11/network-evolution.jpg)
What is HSUPA?
HSUPA means “High Speed Uplink Packet Access” and is a technique used in the UMTS mobile communication system, the upload speeds up to 5.8 Mbit/s.
High Speed Uplink Packet Access (HSUPA) is a transmission method of the UMTS mobile radio standard that allows higher data rates in the uplink and reduces the round trip time (often referred to as ping). HSUPA Category 6 were up to 5.76 Mbit / s and category 9 (Release 9) up to 23 Mbit / s can be achieved. HSUPA is part of Release 9 of UMTS.
What is HSDPA?
HSDPA means “High Speed Downlink Packet Access” and is a technique used in the UMTS mobile communication system, the download speeds of currently 3.6 Mbit/s to 7.2 Mbit/s. HSUPA is developed commercially since 2007 in Germany.
High Speed Downlink Packet Access (HSDPA, 3.5G, 3G + or UMTS broadband) is a data transmission method of the cellular standards UMTS, which was defined by the 3rd Generation Partnership Project. The method enables DSL-like data rates in mobile networks.
HSDPA is available in Germany, among others by the network operators Vodafone, E-Plus, O2, and telecom and in Switzerland by Swisscom, Sunrise and Orange. In Austria operate the A1, T-Mobile, Orange and Three HSDPA networks.
![[圖]](http://www.4gltemall.com/blog/wp-content/uploads/2012/11/GSM-GPRS-EDGE-UMTS-HSDPA-HSUPA-LTE.jpg)
What is LTE?
LTE means “Long Term Evolution” and a mobile radio system with very high data rates. Long Term Evolution (LTE) is a wireless standard of the fourth generation (4G standard), which can carry up to 300 megabits per second to achieve much higher download speeds. The basic scheme of UMTS LTE is maintained. Enables rapid and cost-effective retrofitting the infrastructure of the UMTS technology (3G standard) on LTE-Advanced is possible. LTE-Advanced is backward compatible to LTE.
This entry was posted in 4G Technology and tagged EDGE, GPRS, HSDPA, HSUPA, LTE, UMTS 3G, What is GSM by admin. Bookmark the permalink.
※ 編輯: ott 時間: 2013-07-02 10:10:45
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