The first generation (1G) analog cellular systems supported voice communication with limited roaming. The second generation (2G) digital systems promised higher capacity and better voice quality than did their analog counterparts. The two widely deployed second-generation (2G) cellular systems are GSM (global system for mobile communications) and CDMA (code division multiple access). As was the case with the 1G analog systems, 2G systems were primarily designed to support voice communication. In later releases of these standards, capabilities were introduced to support data transmission.
The 3GPP (3rd Generation Partnership Project) developed 3G systems for efficient data support. The 3GPP2 first introduced the HRPD (high rate packet data) system that used various advanced techniques optimized for data traffic such as channel sensitive scheduling, fast link adaptation and hybrid ARQ, etc.
The fourth generation (4G) of cellular via the Long Term Evolution (LTE) standard was introduced in 3GPP Release 8 as the next major step for UMTS (Universal Mobile Telecommunications System). It provides an enhanced user experience for broadband wireless networks. LTE supports a scalable bandwidth from 1.25 to 20MHz, as well as both FDD (Frequency Division Duplex) and TDD (Time Division Duplex).
The GSM standard was developed as a replacement for first generation (1G) analog cellular networks, and originally described a digital, circuit switched network optimized for full duplex voice telephony. This was expanded over time to include data communications, first by circuit switched transport, then packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS).
Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses Wideband Code Division Multiple Access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators.
High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing 3rd generation mobile telecommunication networks utilizing the WCDMA protocols. A further improved 3GPP standard, Evolved HSPA (also known as HSPA+), was released late in 2008 with subsequent worldwide adoption beginning in 2010. The newer standard allows bit-rates to reach as high as 168 Mbit/s in the downlink and 22 Mbit/s in the uplink.
Time Division Synchronous Code Division Multiple Access (TD-SCDMA) or UTRA/UMTS-TDD 1.28 Mcps Low Chip Rate (LCR), is an air interface found in UMTS mobile telecommunications networks in China as an alternative to W-CDMA. Together with TD-CDMA, it is also known as UMTS-TDD or IMT 2000 Time-Division (IMT-TD).
D-SCDMA was developed in the People’s Republic of China by the Chinese Academy of Telecommunications Technology (CATT), Datang Telecom, and Siemens AG in an attempt to avoid dependence on Western technology. This is likely primarily for practical reasons, since other 3G formats require the payment of patent fees to a large number of Western patent holders.
CDMA is a “spread spectrum” technology, allowing many users to occupy the same time and frequency allocations in a given band/space. CDMA (Code Division Multiple Access) assigns unique codes to each communication to differentiate it from others in the same spectrum. In a world of finite spectrum resources, CDMA enables many more people to share the airwaves at the same time than do alternative technologies.
The CDMA air interface is used in both 2G and 3G networks. 2G CDMA standards are branded cdmaOne™ and include IS-95A and IS-95B. CDMA is the foundation for 3G services: the two dominant IMT-2000 standards, CDMA-2000 and WCDMA, are based on CDMA.
Wi-Fi is a popular technology that allows an electronic device to exchange data wirelessly (using radio waves) over a computer network, including high-speed Internet connections. The Wi-Fi Alliance defines Wi-Fi as any “wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers’ (IEEE) 802.11 standards”. However, since most modern WLANs are based on these standards, the term “Wi-Fi” is used in general English as a synonym for “WLAN”. A device that can use Wi-Fi (such as a personal computer, video-game console, smartphone, tablet, or digital audio player) can connect to a network resource such as the Internet via a wireless network access point. Such an access point (or hotspot) has a range of about 20 meters (65 feet) indoors and a greater range outdoors
Due to WiFi’s growing popularity carriers are now also beginning to integrate it with their own cellular networks. Carrier WiFi can be owned and operated directly or indirectly by the carrier. WiFi is becoming a key focus for mobile carriers as more and more wireless carriers are considering it as a cost effective solution for tackling skyrocketing consumer data demand (and cable carriers wishing to expand their fixed broadband market appeal).
WiMAX (Worldwide Interoperability for Microwave Access) is a wireless communications standard designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. The name “WiMAX” was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as “a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL.
Mobile WiMAX was a replacement candidate for cellular phone technologies such as GSM and CDMA, or can be used as an overlay to increase capacity. Fixed WiMAX is also considered as a wireless backhaul technology for 2G, 3G, and 4G networks in both developed and developing nations.
Long Term Evolution (LTE)
LTE or Long Term Evolution, marketed as 4G LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using a different radio interface together with core network improvements. The standard is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9.
It is the next step in mobile technology evolution, created to improve the 3G phone standard to cope with future demand and faster data services. Amongst its objectives includes improving spectral efficiencies, lowering costs, making use of newly available spectrum, creating the possibility to re-farm, and reallocate spectrum opportunities, and integration with a host of open standards, including those related to Internet Protocol. LTE uses OFDMA (Orthogonal Frequency Division Multiple Access) in the downlink and SCFDMA (Single Carrier-Frequency Division Multiple Access)/DFTS-FDMA (Discrete Fourier Transform Spread-Frequency Division Multiple Access) in the uplink. The system supports multi antenna technologies, whose architecture is called EPS (Evolved Packet System), and is comprised of the E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) on the access side, and Evolved Packet Core (EPC) on the core side.
Small cells is an umbrella term for low-powered radio access nodes that operate in licensed and unlicensed spectrum that have a range of 10 meter to several hundred meters. These contrast with a typical mobile macrocell which might have a range of up to several tens of kilometers. The term covers femtocells, picocells, microcells and metrocells
Small cells provide improved cellular coverage, capacity and applications for homes and enterprises as well as metropolitan and rural public spaces.
Small cells also facilitate a new breed of mobile service that exploits the technology’s ability to detect presence, and connect and interact with existing networks.
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