1.
Code-division multiple access
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Code division multiple access is a channel access method used by various radio communication technologies. CDMA is an example of access, where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies, to permit this without undue interference between the users, CDMA employs spread-spectrum technology and a special coding scheme. CDMA is used as the method in many mobile phone standards. The technology of code division multiple access channels has long been known, in the Soviet Union, the first work devoted to this subject was published in 1935 by professor Dmitriy V. Ageev. It was shown that through the use of methods, there are three types of signal separation, frequency, time and compensatory. LK-1 has a weight of 3 kg, 20–30 km operating distance, the base station, as described by the author, could serve several customers. In 1958, Kupriyanovich made the new experimental pocket model of mobile phone, to serve more customers, Kupriyanovich proposed the device, named by him as correllator. In 1958, the USSR also started the development of the Altai national civil mobile phone service for cars, the phone system weighed 11 kg. It was placed in the trunk of the vehicles of high-ranking officials, the main developers of the Altai system were VNIIS and GSPI. In 1963 this service started in Moscow and in 1970 Altai service was used in 30 USSR cities, one of the early applications for code division multiplexing is in the Global Positioning System. This predates and is distinct from its use in mobile phones, the Qualcomm standard IS-95, marketed as cdmaOne. The Qualcomm standard IS-2000, known as CDMA2000, is used by mobile phone companies. The UMTS 3G mobile phone standard, which uses W-CDMA, CDMA has been used in the OmniTRACS satellite system for transportation logistics. CDMA is a multiple access technique. A spread spectrum technique spreads the bandwidth of the data uniformly for the transmitted power. A spreading code is a code that has a narrow ambiguity function. In CDMA a locally generated code runs at a higher rate than the data to be transmitted
2.
Huawei
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Huawei Technologies Co. Ltd. is a Chinese multinational networking and telecommunications equipment and services company headquartered in Shenzhen, Guangdong. It is the largest telecommunications equipment manufacturer in the world, having overtaken Ericsson in 2012, Huawei was founded in 1987 by Ren Zhengfei, a former engineer in the Peoples Liberation Army. Huawei has over 170,000 employees as of September 2015, around 76,000 of whom are engaged in research and development.4 billion USD in R&D, in 2014, Huawei recorded a profit of 34.2 billion CNY. Its products and services have been deployed in more than 140 countries, Huawei is the official translation of the firms Chinese name. The etymology of the character 华 is derived from 花 which means flower and this is hinted at in Huaweis logo. The character can also mean splendid or magnificent, but nowadays mostly refers to China or Chinese and it is common for Chinese companies to use this word, another example being the Taiwanese company Asus that was founded back in 1989. The second character of Huaweis name, 为, means action or achievement and it is pronounced Wah-Way according to a Gizmodo video that claims to provide the official pronunciation, as well as many other internet sources. However, Wah-Way is incorrect, and is a perpetuation of a mistaken combination of the Cantonese and Mandarin pronunciations for the first and second characters. The Cantonese pronunciation is Wah-Waii, while the Mandarin pronunciation is Hwa-Way, although the company is based in the Cantonese-speaking area of Guangdong, the use of Huawei as the spelling for its name reflects the Mandarin pronunciation the two characters. During the 1980s, Chinas government tried to modernize the countrys underdeveloped telecommunications infrastructure, Ren Zhengfei, a former deputy director of the Peoples Liberation Army engineering corp, founded Huawei in 1987 in Shenzhen. At a time all of Chinas telecommunications technology was imported from abroad. The company reports that it had RMB21,000 in registered capital at the time of its founding, the Far Eastern Economic Review also reported that it received an $8.5 million loan from a state-owned bank, though the company has denied the existence of the loan. During its first several years the business model consisted mainly of reselling private branch exchange switches imported from Hong Kong. Meanwhile, it was reverse-engineering imported switches and investing heavily in research, by 1990 the company had approximately 600 R&D staff, and began its own independent commercialization of PBX switches targeting hotels and small enterprises. The companys first major breakthrough came in 1993, when it launched its C&C08 program controlled telephone switch and it was by far the most powerful switch available in China at the time. By initially deploying in small cities and rural areas and placing emphasis on service and customizability, ahrens writes that these methods were unorthodox, bordering on corrupt, but not illegal. Jiang reportedly agreed with this assessment, Huawei was promoted by both the government and the military as a national champion, and established new research and development offices. In 1997, Huawei won its first overseas contract, providing fixed-line network products to Hong Kong company Hutchison Whampoa, later that year, Huawei launched its wireless GSM-based products and eventually expanded to offer CDMA and UMTS
3.
Evolution-Data Optimized
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Evolution-Data Optimized is a telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. EV-DO is an evolution of the CDMA2000 standard that supports data rates. It uses advanced multiplexing techniques including code division multiple access as well as time division multiplexing to maximize throughput and it is a part of the CDMA2000 family of standards and has been adopted by many mobile phone service providers around the world particularly those previously employing CDMA networks. It is also used on the Globalstar satellite phone network, EV-DO service has been or will be discontinued in much of Canada in 2015. An EV-DO channel has a bandwidth of 1.25 MHz, the channel structure, on the other hand, is very different. Additionally, the network is entirely packet-based, and thus is not constrained by the restrictions typically present on a circuit switched network. The EV-DO feature of CDMA2000 networks provides access to devices with forward link air interface speeds of up to 2.4 Mbit/s with Rel.0. The reverse link rate for Rel.0 can operate up to 153 kbit/s, a can operate at up to 1.8 Mbit/s. It was designed to be operated end-to-end as an IP based network, there have been several revisions of the standard, starting with Release 0. This was later expanded upon with Revision A to support Quality of Service and higher rates on the forward link, later in 2006 Revision B was published, that among other features includes the ability to bundle multiple carriers to achieve even higher rates and lower latencies. B involves a software update to the cell site modem, existing cdma2000 operators may also have to retune some of their existing 1xRTT channels to other frequencies, since Rev. B requires all DO carriers be within 5 MHz, initially, the standard was called High Data Rate, but was renamed to 1xEV-DO after it was ratified by the International Telecommunication Union under the designation TIA-856. Originally, 1xEV-DO stood for 1x Evolution-Data Only, referring to its being an evolution of the 1x air interface standard. The title of the 1xEV-DO standard document is cdma2000 High Rate Packet Data Air Interface Specification, as cdma2000 is another name for the 1x standard, numerically designated as TIA-2000. Later, likely due to the negative connotations of the word only. So EV-DO now stands for Evolution-Data Optimized, the 1x prefix has been dropped by many of the major carriers, and is marketed simply as EV-DO. This provides a more marketing-friendly emphasis that the technology was optimized for data, the primary characteristic that differentiates an EV-DO channel from a 1xRTT channel is that it is time multiplexed on the forward link. This means that a mobile has full use of the forward traffic channel within a particular geographic area during a given slot of time
4.
Mobile broadband modem
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A mobile Internet user can connect using a wireless modem to a wireless Internet Service Provider to get Internet access. The next generation of phones, known as 2G, were digital, a further evolution called HSCSD used multiple GSM channels to support up to 43. 2kbit/s. All of these technologies still required their users to have a dial-up ISP to connect to, the release of 2. 5G phones with support for packet data changed this. The 2. 5G networks break both digital voice and data into chunks, and mix both onto the network simultaneously in a process called packet switching. This allows the phone to have a connection and a data connection at the same time. The network can link the data connection into a company network and this allows web browsing on the phone, but a PC can also tap into this service if it connects to the phone. The PC needs to send a special number to the phone to get access to the packet data connection. From the PCs viewpoint, the connection still looks like a normal PPP dial-up link, but it is all terminating on the phone, speeds on 2. 5G networks are usually in the 30–50kbit/s range. 3G networks have taken this approach to a level, using different underlying technology. They routinely provide speeds over 300kbit/s, due to the now increased internet speed, internet connection sharing via WLAN has become a workable reality. Devices which allow internet connection sharing or other types of routing on cellular networks are called also cellular routers, a further evolution is the 3. 5G technology HSDPA, which provides speeds of multiple Megabits per second. Several of the network operators that provide 3G or faster wireless internet access offer plans and wireless modems that enable computers to connect to. These wireless modems are typically in the form of a small USB based device or a small, wiMAX based services that provide high speed wireless internet access are available in some countries and also rely on wireless modems that connect to the providers wireless network. Wireless USB Modems are nicknamed as Dongles, early 3G mobile broadband modems used the PCMCIA or ExpressCard ports, commonly found on legacy laptops. Major producers are Huawei, Option N. V. Novatel Wireless, more recently, the expression connect card is also used to identify internet USB keys. Vodafone brands this type of device as a Vodem, often a mobile network operator will supply a locked modem or other wireless device that can only be used on their network. It is possible to use online unlocking services that will remove the lock so the device accepts SIM cards from any network, standalone mobile broadband modems are designed to be connected directly to one computer. In the past the PCMCIA and ExpressCard standards were used to connect to the computer, as USB connectivity became almost universal, these various standards were largely superseded by USB modems in the early 21st century
5.
3G
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3G, short for third generation, is the third generation of wireless mobile telecommunications technology. Later 3G releases, often denoted 3. 5G and 3. 75G, also mobile broadband access of several Mbit/s to smartphones. This ensures it can be applied to voice telephony, mobile Internet access, fixed wireless Internet access, video calls. A new generation of cellular standards has appeared approximately every year since 1G systems were introduced in 1981/1982. Each generation is characterized by new bands, higher data rates. The first 3G networks were introduced in 1998 and fourth generation 4G networks in 2008, several telecommunications companies market wireless mobile Internet services as 3G, indicating that the advertised service is provided over a 3G wireless network. Services advertised as 3G are required to meet IMT-2000 technical standards, including standards for reliability, to meet the IMT-2000 standards, a system is required to provide peak data rates of at least 200 kbit/s. However, many services advertised as 3G provide higher speed than the technical requirements for a 3G service. Recent 3G releases, often denoted 3. 5G and 3. 75G, also mobile broadband access of several Mbit/s to smartphones. The cell phones are typically UMTS and GSM hybrids, several radio interfaces are offered, sharing the same infrastructure, The original and most widespread radio interface is called W-CDMA. The TD-SCDMA radio interface was commercialized in 2009 and is offered in China. The latest UMTS release, HSPA+, can provide data rates up to 56 Mbit/s in the downlink in theory and 22 Mbit/s in the uplink. The CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in North America and South Korea, the cell phones are typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev B offers peak rates of 14.7 Mbit/s downstream, the above systems and radio interfaces are based on spread spectrum radio transmission technology. It is based on the three times as efficient 8PSK modulation scheme as supplement to the original GMSK modulation scheme, EDGE is still used extensively due to its ease of upgrade from existing 2G GSM infrastructure and cell-phones. However, in practice EDGE is seldom marketed as a 3G system, EDGE was also a mode in the IS-136 TDMA system, today ceased. Evolved EDGE, the latest revision, has peaks of 1 Mbit/s downstream and 400 kbit/s upstream, the Universal Mobile Telecommunications System, created and revised by the 3GPP. The family is a revision from GSM in terms of encoding methods and hardware
6.
Mobile phone
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A mobile phone is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the systems of a mobile phone operator. Most modern mobile telephone services use a network architecture, and, therefore. Mobile phones which offer these and more general computing capabilities are referred to as smartphones, the first handheld mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing c.4.4 lbs. In 1983, the DynaTAC 8000x was the first commercially available mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to seven billion, penetrating 100% of the global population. In first quarter of 2016, the top smartphone manufacturers were Samsung, Apple, a handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a pocket-size folding telephone with a thin carbon microphone. Early predecessors of cellular phones included analog radio communications from ships, the race to create truly portable telephone devices began after World War II, with developments taking place in many countries. These 0G systems were not cellular, supported few simultaneous calls, the first handheld mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing c.4.4 lbs. The first commercial automated cellular network was launched in Japan by Nippon Telegraph and this was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone system in Denmark, Finland, Norway, and Sweden. Several other countries followed in the early to mid-1980s. These first-generation systems could support far more simultaneous calls but still used analog cellular technology, in 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone. In 1991, the digital cellular technology was launched in Finland by Radiolinja on the GSM standard. This sparked competition in the sector as the new operators challenged the incumbent 1G network operators, ten years later, in 2001, the third generation was launched in Japan by NTT DoCoMo on the WCDMA standard. This was followed by 3. 5G, 3G+ or turbo 3G enhancements based on the high-speed packet access family, allowing UMTS networks to have data transfer speeds. By 2009, it had become clear that, at point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications. Consequently, the industry began looking to data-optimized fourth-generation technologies, with the promise of speed improvements up to ten-fold over existing 3G technologies
7.
Cell site
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In Global System for Mobile Communications networks, the correct term is Base Transceiver Station, and colloquial synonyms are mobile phone mast or base station. The term base station site might better reflect the increasing co-location of multiple mobile operators, depending on an operators technology, even a site hosting just a single mobile operator may house multiple base stations, each to serve a different air interface technology. Some cities require that sites be inconspicuous, they can be blended with the surrounding area or mounted on buildings or advertising towers. Preserved treescapes can often hide cell towers inside a tree or preserved tree. These installations are generally referred to as concealed cell sites or stealth cell sites, the working range of a cell site is not a fixed figure. It will depend on a number of factors, including, but not limited to, the frequency of signal in use. Timing limitations in some technologies The transmitters rated power, the required uplink/downlink data rate of the subscribers device The directional characteristics of the site antenna array. Reflection and absorption of energy by buildings or vegetation. It may also be limited by geographical or regulatory factors. Generally, in areas where there are enough cell sites to cover a wide area, Ensure that the overlap area is not too large, to minimize interference problems with other sites. In practice, cell sites are grouped in areas of population density. Cell phone traffic through a site is limited by the base stations capacity. This limitation is another factor affecting the spacing of cell mast sites, in suburban areas, masts are commonly spaced 1–2 miles apart and in dense urban areas, masts may be as close as ¼-½ mile apart. The maximum range of a mast depends on the same circumstances, some technologies, such as GSM, normally have a fixed maximum range of 35 kilometres, which is imposed by technical limitations. CDMA and IDEN have no limit, but the limiting factor is the ability of a low-powered personal cell phone to transmit back to the mast. As a rough guide, based on a tall mast and flat terrain, when the terrain is hilly, the maximum distance can vary from as little as 5 kilometres to 8 kilometres due to encroachment of intermediate objects into the wide center fresnel zone of the signal. Depending on terrain and other circumstances, a GSM Tower can replace between 2 and 50 miles of cabling for fixed wireless networks, the concept of maximum range is misleading, however, in a cellular network. Cellular networks are designed to support many conversations with a number of radio channels that are licensed to an operator of a cellular service
8.
CdmaOne
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Interim Standard 95 was the first ever CDMA-based digital cellular technology. It was developed by Qualcomm and later adopted as a standard by the Telecommunications Industry Association in TIA/EIA/IS-95 release published in 1995, the proprietary name for IS-95 is cdmaOne. It is a 2G mobile telecommunications standard that uses CDMA, an access scheme for digital radio, to send voice, data. CDMA or code division multiple access is a radio system that transmits streams of bits. CDMA permits several radios to share the same frequencies, unlike TDMA time division multiple access, a competing system used in 2G GSM, all radios can be active all the time, because network capacity does not directly limit the number of active radios. In North America, the technology competed with Digital AMPS and it is now being supplanted by IS-2000, a later CDMA-based standard. CdmaOnes technical history is reflective of both its birth as a Qualcomm internal project, and the world of then-unproven competing digital cellular standards under which it was developed, the term IS-95 generically applies to the earlier set of protocol revisions, namely P_REVs one through five. P_REV=1 was developed under an ANSI standards process with documentation reference J-STD-008, J-STD-008, published in 1995, was only defined for the then-new North American PCS band. The term IS-95 properly refers to P_REV=1, developed under the Telecommunications Industry Association standards process, IS-95 offered interoperation with the analog cellular network. For digital operation, IS-95 and J-STD-008 have most technical details in common, the immature style and structure of both documents are highly reflective of the standardizing of Qualcomms internal project. P_REV=2 is termed Interim Standard 95A, IS-95A was developed for Band Class 0 only, as in incremental improvement over IS-95 in the TIA standards process. P_REV=3 is termed Technical Services Bulletin 74, tSB-74 was the next incremental improvement over IS-95A in the TIA standards process. P_REV=4 is termed Interim Standard 95B Phase I, and P_REV=5 is termed Interim Standard 95B Phase II, p_REV=4 was by far the most popular variant of IS-95, with P_REV=5 only seeing minimal uptake in South Korea. P_REV=6 and beyond fall under the CDMA2000 umbrella, besides technical improvements, the IS-2000 documents are much more mature in terms of layout and content. They also provide backwards-compatibility to IS-95, the IS-95 standards describe an air interface, a set of protocols used between mobile units and the network. IS-95 defines the transmission of signals in both the forward and reverse directions, in the forward direction, radio signals are transmitted by base stations. Every BTS is synchronized with a GPS receiver so transmissions are tightly controlled in time, all forward transmissions are QPSK with a chip rate of 1,228,800 per second. Each signal is spread with a Walsh code of length 64, for the reverse direction, radio signals are transmitted by the mobile
9.
UMTS
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The Universal Mobile Telecommunications System is a third generation mobile cellular system for networks based on the GSM standard. UMTS uses wideband code division multiple access radio access technology to offer greater spectral efficiency, UMTS specifies a complete network system, which includes the radio access network, the core network and the authentication of users via SIM cards. The technology described in UMTS is sometimes referred to as Freedom of Mobile Multimedia Access or 3GSM. Unlike EDGE and CDMA2000, UMTS requires new base stations and new frequency allocations, UMTS supports maximum theoretical data transfer rates of 42 Mbit/s when Evolved HSPA is implemented in the network. Users in deployed networks can expect a transfer rate of up to 384 kbit/s for Release 99 handsets, since 2006, UMTS networks in many countries have been or are in the process of being upgraded with High-Speed Downlink Packet Access, sometimes known as 3. 5G. Currently, HSDPA enables downlink transfer speeds of up to 21 Mbit/s, work is also progressing on improving the uplink transfer speed with the High-Speed Uplink Packet Access. The first national consumer UMTS networks launched in 2002 with a emphasis on telco-provided mobile applications such as mobile TV. UMTS combines three different terrestrial air interfaces, GSMs Mobile Application Part core, and the GSM family of speech codecs, the air interfaces are called UMTS Terrestrial Radio Access. All air interface options are part of ITUs IMT-2000, in the currently most popular variant for cellular mobile telephones, W-CDMA is used. Please note that the terms W-CDMA, TD-CDMA and TD-SCDMA are misleading, while they suggest covering just a channel access method, they are actually the common names for the whole air interface standards. W-CDMA or WCDMA, along with UMTS-FDD, UTRA-FDD, or IMT-2000 CDMA Direct Spread is an air interface found in 3G mobile telecommunications networks. W-CDMA uses the DS-CDMA channel access method with a pair of 5 MHz wide channels, in contrast, the competing CDMA2000 system uses one or more available 1.25 MHz channels for each direction of communication. W-CDMA systems are criticized for their large spectrum usage, which delayed deployment in countries that acted relatively slowly in allocating new frequencies specifically for 3G services. The specific frequency bands originally defined by the UMTS standard are 1885–2025 MHz for the mobile-to-base, in the US, 1710–1755 MHz and 2110–2155 MHz are used instead, as the 1900 MHz band was already used. Some carriers such as T-Mobile use band numbers to identify the UMTS frequencies, in the late 1990s, W-CDMA was developed by NTT DoCoMo as the air interface for their 3G network FOMA. Later NTT DoCoMo submitted the specification to the International Telecommunication Union as a candidate for the international 3G standard known as IMT-2000. The ITU eventually accepted W-CDMA as part of the IMT-2000 family of 3G standards, as an alternative to CDMA2000, EDGE, later, W-CDMA was selected as an air interface for UMTS. As NTT DoCoMo did not wait for the finalisation of the 3G Release 99 specification, however, this has been resolved by NTT DoCoMo updating their network
10.
International Telecommunication Union
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ITU, based in Geneva, Switzerland, is a member of the United Nations Development Group. ITU has been an intergovernmental public-private partnership organization since its inception, ITU was formed in 1865, in Paris, at the International Telegraph Convention, this makes it one of the oldest intergovernmental organizations in the world. ITU became a United Nations specialized agency in 1947, the ITU comprises three sectors, each managing a different aspect of the matters handled by the Union, as well as ITU Telecom. The sectors were created during the restructuring of ITU at its 1992 Plenipotentiary Conference, radiocommunication Established in 1927 as the International Radio Consultative Committee or CCIR, this sector manages the international radio-frequency spectrum and satellite orbit resources. In 1992, the CCIR became the ITU-R, Standardization Standardization was the original purpose of ITU since its inception. Established in 1956 as the International Telephone and Telegraph Consultative Committee or CCITT, in 1993, the CCITT became the ITU-T. Development Established in 1992, this sector helps spread equitable, sustainable and affordable access to information and communication technologies, ITU Telecom ITU Telecom organizes major events for the worlds ICT community. A permanent General Secretariat, headed by the Secretary General, manages the work of the Union. The basic texts of the ITU are adopted by the ITU Plenipotentiary Conference, the ITU is headed by a Secretary-General, who is elected to a four-year term by the member states at the ITU Plenipotentiary Conference. On 23 October 2014 Houlin Zhao was elected 19th Secretary-General of the ITU at the Plenipotentiary Conference in Busan and his four-year mandate started on 1 January 2015, and he was formally inaugurated on 15 January 2015. There are 193 Member States of the ITU, which are all UN member states, the most recent member state to join the ITU is South Sudan, which became a member on 14 July 2011. The Republic of China was blocked from membership by the Peoples Republic of China, palestine was admitted as an observer in 2010. The Summit was held as two conferences in 2003 and 2005 in Geneva and Tunis, respectively, with the aim of bridging the digital divide, in December 2012, the ITU facilitated The World Conference on International Telecommunications 2012 in Dubai. WCIT-12 was a conference to address International Telecommunications Regulations, the international rules for telecommunications. The previous conference to update the Regulations was held in Melbourne in 1988, in August 2012, ITU called for a public consultation on a draft document ahead of the conference. Telecommunications ministers from 193 countries attended the conference in Dubai, the current regulatory structure was based on voice telecommunications, when the Internet was still in its infancy. In 1988, telecommunications operated under regulated monopolies in most countries, as the Internet has grown, organizations such as ICANN have come into existence to manage key resources such as Internet addresses and Domain Names. Some outside the United States believe that the United States exerts too much influence over the governance of the Internet, current proposals look to take into account the prevalence of data communications
11.
Telecommunications Industry Association
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The Telecommunications Industry Assocs most widely adopted standards include, TIA-942 Telecommunications Infrastructure Standard for Data Centers TIA-568-C. TIA is a standards organization of the ITU-T Global Standards Collaboration initiative. The TIA2012 is Conference & Exhibition, scheduled for June 5–7 at the Gaylord Hotel in Dallas, Texas, focused on innovation and thought leadership, TIA2012 is the annual gathering of the community of technology suppliers that form the foundation of the global communications experience. TIA2012 is the annual community gathering of all who create, distribute and use network technologies, network engineers and designers, product managers. TIA Now is a media outlet of TIA that informs about ICT trends, event. They interview top level executives and thought leaders that shape the development of the information and communication industry ICT and it delivers a perspective on policy, industry news, new technologies and evolving business strategies designed to inform and educate an audience of ICT decision-makers
12.
Duplex (telecommunications)
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A duplex communication system requires a pair of channels/frequencies hence the term duplex meaning two parts. The two channels are defined as uplink/downlink or reverse/forward, in a full-duplex system simultaneous transmission/reception is available, i. e. One can transmit and receive simultaneously, in a half-duplex system, each party can communicate with the other but not simultaneously, the communication is one direction at a time. Half duplex systems utilize separate channels for uplink and downlink, i. e. a transmit, in a half duplex communications system one user is allowed to transmit on the uplink channel at a time. The transmitted uplink signal is frequency translated via a radio/repeater to the downlink receive frequency which is received by all other radios tuned to the downlink/receive frequency. A half-duplex system is defined as system which operates two, hence duplex, dedicated uplink/downlink channels/frequencies. In a half duplex system a single path is provided for uplink, all uplink messages are broadcast via the downlink channel to all users simultaneously via a repeater which performs uplink to downlink channel/frequency translation. All cellular and land line PSTNs and PDSNs are full duplex systems, all full duplex systems require a channel/frequency translator via a radio/repeater. This is required in order to translate the uplink/transmit transmission from one to the downlink/receive channel/frequency of user two. Full duplex systems are one to one private systems unlike half duplex systems which broadcast to all users and this effectively makes the cable itself a collision-free environment and doubles the maximum total transmission capacity supported by each Ethernet connection. Time-division duplexing is commonly referred to as simplex communications, a single channel/frequency is employed for bidirectional communications. The term simplex communication as applied to TDM single channel systems predates the term TDD by at least 80 years, frequency-division duplexing as with any other duplex system is defined by two channel/frequency simultaneous communication. A channel/frequency pair are assigned to individual user on the system. An FDD system requires frequency translation from user 1 uplink/reverse frequency to user 2 downlink/forward frequency, full-duplex audio systems like telephones can create echo, which needs to be removed. Echo occurs when the coming out of the speaker, originating from the far end. The sound then reappears at the source end, but delayed. This feedback path may be acoustic, through the air, or it may be mechanically coupled, echo cancellation is a signal-processing operation that subtracts the far-end signal from the microphone signal before it is sent back over the network. Echo cancellation is important to the V.32, V.34, V.56, echo cancelers are available as both software and hardware implementations
13.
Orthogonality
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The concept of orthogonality has been broadly generalized in mathematics, as well as in areas such as chemistry, and engineering. The word comes from the Greek ὀρθός, meaning upright, and γωνία, the ancient Greek ὀρθογώνιον orthogōnion and classical Latin orthogonium originally denoted a rectangle. Later, they came to mean a right triangle, in the 12th century, the post-classical Latin word orthogonalis came to mean a right angle or something related to a right angle. In geometry, two Euclidean vectors are orthogonal if they are perpendicular, i. e. they form a right angle, two vectors, x and y, in an inner product space, V, are orthogonal if their inner product ⟨ x, y ⟩ is zero. This relationship is denoted x ⊥ y, two vector subspaces, A and B, of an inner product space, V, are called orthogonal subspaces if each vector in A is orthogonal to each vector in B. The largest subspace of V that is orthogonal to a subspace is its orthogonal complement. Given a module M and its dual M∗, an element m′ of M∗, two sets S′ ⊆ M∗ and S ⊆ M are orthogonal if each element of S′ is orthogonal to each element of S. A term rewriting system is said to be if it is left-linear and is non-ambiguous. Orthogonal term rewriting systems are confluent, a set of vectors in an inner product space is called pairwise orthogonal if each pairing of them is orthogonal. Such a set is called an orthogonal set, nonzero pairwise orthogonal vectors are always linearly independent. In certain cases, the normal is used to mean orthogonal. For example, the y-axis is normal to the curve y = x2 at the origin, however, normal may also refer to the magnitude of a vector. In particular, a set is called if it is an orthogonal set of unit vectors. As a result, use of the normal to mean orthogonal is often avoided. The word normal also has a different meaning in probability and statistics, a vector space with a bilinear form generalizes the case of an inner product. When the bilinear form applied to two results in zero, then they are orthogonal. The case of a pseudo-Euclidean plane uses the term hyperbolic orthogonality, in the diagram, axes x′ and t′ are hyperbolic-orthogonal for any given ϕ. In 2-D or higher-dimensional Euclidean space, two vectors are orthogonal if and only if their dot product is zero, i. e. they make an angle of 90°, hence orthogonality of vectors is an extension of the concept of perpendicular vectors into higher-dimensional spaces
14.
In-phase and quadrature components
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In electrical engineering, a sinusoid with angle modulation can be decomposed into, or synthesized from, two amplitude-modulated sinusoids that are offset in phase by one-quarter cycle. All three functions have the same frequency, the amplitude modulated sinusoids are known as in-phase and quadrature components. Some authors find it convenient to refer to only the amplitude modulation itself by those terms. In vector analysis, a vector with polar coordinates A, φ and Cartesian coordinates x = A cos, y = A sin, can be represented as the sum of orthogonal components, similarly in trigonometry, the expression sin can be represented by sin cos + sin sin. And in functional analysis, when x is a function of some variable, such as time, these components are sinusoids. When φ =0, sin reduces to just the in-phase component sin cos, and we now note that many authors prefer the identity cos = cos cos + cos sin, in which case cos cos is the in-phase component. In both conventions cos is the amplitude modulation, which explains why some authors refer to it as the actual in-phase component. We can also observe that in both conventions the quadrature component leads the in-phase component by one-quarter cycle, the term alternating current applies to a voltage vs time function that is sinusoidal with a frequency, f, of 50 or 60 Hz. When it is applied to a circuit or device, it causes a current that is also sinusoidal. And in general there is a constant phase difference, φ, the sinusoidal voltage stimulus is usually defined to have zero phase, meaning that it is arbitrarily chosen as a convenient time reference. So the phase difference is attributed to the current function, e. g. sin , whose components are sin cos and sin sin . When φ happens to be such that the component is zero, the current and voltage sinusoids are said to be in quadrature. In that case, no power is consumed. Rather it is stored by the device and given back. Note that the term in quadrature only implies that two sinusoids are orthogonal, not that they are components of another sinusoid. In an angle modulation application, with carrier frequency ƒ, φ is also a time-variant function, giving, because of the modulation, the components are no longer completely orthogonal functions. But when A and φ are slowly varying functions compared to 2 π f t, authors often call it a narrowband assumption, or a narrowband signal model. Orthogonality is important in applications, including demodulation, direction-finding
15.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, in the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that Julius Caesar used pigeons as messengers in his conquest of Gaul. The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons, in the early 19th century, the Dutch government used the system in Java and Sumatra. And in 1849, Paul Julius Reuter started a service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
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Wireless
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Wireless communication, or sometimes simply wireless, is the transfer of information or power between two or more points that are not connected by an electrical conductor. The most common wireless technologies use radio waves, with radio waves distances can be short, such as a few meters for television or as far as thousands or even millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including radios, cellular telephones, personal digital assistants. Somewhat less common methods of achieving wireless communications include the use of other wireless technologies, such as light, magnetic. The term wireless has been used twice in history, with slightly different meaning. It was initially used from about 1890 for the first radio transmitting and receiving technology, as in wireless telegraphy and this became its primary usage in the 2000s, due to the advent of technologies such as LTE, LTE-Advanced, Wi-Fi and Bluetooth. Wireless operations permit services, such as communications, that are impossible or impractical to implement with the use of wires. The term is used in the telecommunications industry to refer to telecommunications systems which use some form of energy to transfer information without the use of wires. Information is transferred in this manner over both short and long distances, similar to free-space optical communication, the photophone also required a clear line of sight between its transmitter and its receiver. It would be decades before the photophones principles found their first practical applications in military communications. Marconi soon developed a system that was transmitting signals way beyond distances anyone could have predicted, guglielmo Marconi and Karl Ferdinand Braun were awarded the 1909 Nobel Prize for Physics for their contribution to this form of wireless telegraphy. Free space means the light travel through the open air or outer space. This contrasts with other technologies that use light beams traveling through transmission lines such as optical fiber or dielectric light pipes. The technology is useful where physical connections are due to high costs or other considerations. Sonic, especially ultrasonic short range communication involves the transmission and reception of sound, electromagnetic induction has short range communication and power. This has been used in situations such as pacemakers, as well as for short-range Rfid tags. Common examples of wireless equipment include, Infrared and ultrasonic remote control devices Professional LMR and SMR typically used by business, industrial, consumer Two-way radio including FRS Family Radio Service, GMRS and Citizens band radios. Consumer and professional Marine VHF radios, airband and radio navigation equipment used by aviators and air traffic control Cellular telephones and pagers, provide connectivity for portable and mobile applications, both personal and business
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Radio
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When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form, Radio systems need a transmitter to modulate some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation. Radio systems also need an antenna to convert electric currents into radio waves, an antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected, the electromagnetic wave is intercepted by a tuned receiving antenna. Radio frequencies occupy the range from a 3 kHz to 300 GHz, a radio communication system sends signals by radio. The term radio is derived from the Latin word radius, meaning spoke of a wheel, beam of light, however, this invention would not be widely adopted. The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world, the United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram, the term started to become preferred by the general public in the 1920s with the introduction of broadcasting. Radio systems used for communication have the following elements, with more than 100 years of development, each process is implemented by a wide range of methods, specialised for different communications purposes. Each system contains a transmitter, This consists of a source of electrical energy, the transmitter contains a system to modulate some property of the energy produced to impress a signal on it. This modulation might be as simple as turning the energy on and off, or altering more subtle such as amplitude, frequency, phase. Amplitude modulation of a carrier wave works by varying the strength of the signal in proportion to the information being sent. For example, changes in the strength can be used to reflect the sounds to be reproduced by a speaker. It was the used for the first audio radio transmissions. Frequency modulation varies the frequency of the carrier, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal. FM has the capture effect whereby a receiver only receives the strongest signal, Digital data can be sent by shifting the carriers frequency among a set of discrete values, a technique known as frequency-shift keying. FM is commonly used at Very high frequency radio frequencies for high-fidelity broadcasts of music, analog TV sound is also broadcast using FM. Angle modulation alters the phase of the carrier wave to transmit a signal
18.
Internet access
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Internet access is the process that enables individuals and organisations to connect to the Internet using computer terminals, computers, mobile devices, sometimes via computer networks. Once connected to the Internet, users can access Internet services, such as email, Internet service providers offer Internet access through various technologies that offer a wide range of data signaling rates. Consumer use of the Internet first became popular through dial-up Internet access in the 1990s, by the first decade of the 21st century, many consumers in developed nations used faster, broadband Internet access technologies. By 2014 this was almost ubiquitous worldwide, with an average connection speed exceeding 4 Mbit/s. Use by a wider audience came in 1995 when restrictions on the use of the Internet to carry commercial traffic were lifted. LANs typically operated at 10 Mbit/s, while modem data-rates grew from 1200 bit/s in the early 1980s, initially, dial-up connections were made from terminals or computers running terminal emulation software to terminal servers on LANs. These dial-up connections did not support use of the Internet protocols. Broadband connections are made using a computers built in Ethernet networking capabilities. Most broadband services provide a continuous always on connection, there is no dial-in process required, made broadband Internet access a public policy issue. In 2000, most Internet access to homes was provided using dial-up, while many businesses, in 2000 there were just under 150 million dial-up subscriptions in the 34 OECD countries and fewer than 20 million broadband subscriptions. By 2004, broadband had grown and dial-up had declined so that the number of subscriptions were roughly equal at 130 million each, the broadband technologies in widest use are ADSL and cable Internet access. Newer technologies include VDSL and optical fibre extended closer to the subscriber in telephone and cable plants. In areas not served by ADSL or cable, some community organizations, Wireless and satellite Internet are often used in rural, undeveloped, or other hard to serve areas where wired Internet is not readily available. Newer technologies being deployed for fixed and mobile broadband access include WiMAX, LTE, starting in roughly 2006, mobile broadband access is increasingly available at the consumer level using 3G and 4G technologies such as HSPA, EV-DO, HSPA+, and LTE. Some libraries provide stations for physically connecting users laptops to local area networks, Wireless Internet access points are available in public places such as airport halls, in some cases just for brief use while standing. Some access points may also provide coin-operated computers, various terms are used, such as public Internet kiosk, public access terminal, and Web payphone. Many hotels also have public terminals, usually fee based and these services may be free to all, free to customers only, or fee-based. A Wi-Fi hotspot need not be limited to a location since multiple ones combined can cover a whole campus or park
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Multiplexing
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In telecommunications and computer networks, multiplexing is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share an expensive resource, for example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910, the multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the channel into several logical channels. A reverse process, known as demultiplexing, extracts the original channels on the receiver end, a device that performs the multiplexing is called a multiplexer, and a device that performs the reverse process is called a demultiplexer. Multiple variable bit rate digital bit streams may be transferred efficiently over a fixed bandwidth channel by means of statistical multiplexing. This is an asynchronous mode time-domain multiplexing which is a form of time-division multiplexing, digital bit streams can be transferred over an analog channel by means of code-division multiplexing techniques such as frequency-hopping spread spectrum and direct-sequence spread spectrum. In wired communication, space-division multiplexing, also known as Space-division multiple access is the use of separate point-to-point electrical conductors for each transmitted channel, in wireless communication, space-division multiplexing is achieved with multiple antenna elements forming a phased array antenna. Examples are multiple-input and multiple-output, single-input and multiple-output and multiple-input and single-output multiplexing, different antennas would give different multi-path propagation signatures, making it possible for digital signal processing techniques to separate different signals from each other. These techniques may also be utilized for space diversity or beamforming rather than multiplexing Frequency-division multiplexing is inherently an analog technology, FDM achieves the combining of several signals into one medium by sending signals in several distinct frequency ranges over a single medium. In FDM the signals are electrical signals, one of the most common applications for FDM is traditional radio and television broadcasting from terrestrial, mobile or satellite stations, or cable television. Only one cable reaches a customers residential area, but the provider can send multiple television channels or signals simultaneously over that cable to all subscribers without interference. Receivers must tune to the frequency to access the desired signal. A variant technology, called wavelength-division multiplexing is used in optical communications, time-division multiplexing is a digital technology which uses time, instead of space or frequency, to separate the different data streams. TDM involves sequencing groups of a few bits or bytes from each individual input stream, one after the other, if done sufficiently quickly, the receiving devices will not detect that some of the circuit time was used to serve another logical communication path. Consider an application requiring four terminals at an airport to reach a central computer, each terminal communicated at 2400 baud, so rather than acquire four individual circuits to carry such a low-speed transmission, the airline has installed a pair of multiplexers. A pair of 9600 baud modems and one dedicated analog communications circuit from the ticket desk back to the airline data center are also installed
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4G
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4G is the fourth generation of wireless mobile telecommunications technology, succeeding 3G. A 4G system must provide capabilities defined by ITU in IMT Advanced, potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, and 3D television. The first-release Long Term Evolution standard has been deployed in Oslo, Norway. It has, however, been debated whether first-release versions should be considered 4G, since the first-release versions of Mobile WiMAX and LTE support much less than 1 Gbit/s peak bit rate, they are not fully IMT-Advanced compliant, but are often branded 4G by service providers. According to operators, a generation of the network refers to the deployment of a new non-backward-compatible technology, as opposed to earlier generations, a 4G system does not support traditional circuit-switched telephony service, but all-Internet Protocol based communication such as IP telephony. The peak bit rate is improved by smart antenna arrays for multiple-input multiple-output communications. New mobile generations have appeared about ten years since the first move from 1981 analog to digital transmission in 1992. In the mid-1990s, the ITU-R standardization organization released the IMT-2000 requirements as a framework for what standards should be considered 3G systems, in 2008, ITU -R specified the IMT - Advanced requirements for 4G systems. In theory speeds up to 672 Mbit/s are possible, but have not been deployed yet, the fastest 3G-based standard in the CDMA2000 family is the EV-DO Rev. B, which is available since 2010 and offers 15.67 Mbit/s downstream. This article refers to 4G using IMT-Advanced, as defined by ITU-R, an IMT-Advanced cellular system must fulfill the following requirements, Be based on an all-IP packet switched network. Have peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access, be able to dynamically share and use the network resources to support more simultaneous users per cell. Use scaleable channel bandwidths of 5–20 MHz, optionally up to 40 MHz. Rumney, IMT-Advanced, 4G Wireless Takes Shape in an Olympic Year. Have peak link spectral efficiency of 15-bit/s/Hz in the downlink, and 6. 75-bit/s/Hz in the up link, system spectral efficiency is, in indoor cases, 3-bit/s/Hz/cell for downlink and 2. 25-bit/s/Hz/cell for up link. In September 2009, the proposals were submitted to the International Telecommunication Union as 4G candidates. Basically all proposals are based on two technologies, LTE Advanced standardized by the 3GPP802. The latters standard versions were ratified in spring 2011, but are far from being implemented. The first set of 3GPP requirements on LTE Advanced was approved in June 2008, LTE Advanced was to be standardized in 2010 as part of Release 10 of the 3GPP specification. LTE Advanced will be based on the existing LTE specification Release 10, a summary of the technologies that have been studied as the basis for LTE Advanced is included in a technical report
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Qualcomm
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Qualcomm is an American multinational semiconductor and telecommunications equipment company that designs and markets wireless telecommunications products and services. It derives most of its revenue from chipmaking and the bulk of its profit from patent licensing businesses, the company headquarters are located in San Diego, California, United States, and has 224 worldwide locations. The parent company is Qualcomm Incorporated, which includes the Qualcomm Technology Licensing Division, Jacobs and Viterbi had previously founded Linkabit. In 1990, Qualcomm began the design of the first CDMA-based cellular base station and this work began as a study contract from AirTouch which was facing a shortage of cellular capacity in Los Angeles. Two years later Qualcomm began to manufacture CDMA cell phones, base stations, the initial base stations were not reliable and the technology was licensed wholly to Nortel in return for their work in improving the base station switching. The first CDMA technology was standardized as IS-95, Qualcomm has since helped to establish the CDMA2000, WCDMA and LTE cellular standards. The following year, Qualcomm acquired Eudora, a client for PC that could be used with the OmniTRACS system. The acquisition associated a widely used email client with a company that was little-known at the time, in 1997, Qualcomm paid $18 million for the naming rights to the Jack Murphy Stadium in San Diego, renaming it to Qualcomm Stadium. The naming rights belong to Qualcomm until 2017. In 1999, Qualcomm sold its base station business to Ericsson, the company was now focused on developing and licensing wireless technologies and selling ASICs that implement them. Steve Mollenkopf was promoted to president and chief operating officer of the company, mollenkopfs appointment as CEO was announced on December 13,2013 and took effect on March 4,2014. He succeeded Paul E. Jacobs, who remains executive chairman, CFO Bill Keitel retired and was replaced by Applied Materials CFO George Davis on March 11,2013. Vista Equity Partners took over the Omnitracs business from Qualcomm Incorporated in November 2013, in October 2014, Qualcomm wrapped up a deal for chip maker CSR Plc for a fee of $2.5 billion, beating its biggest rival Microchip Technology. However, surprised by the release of the 64-bit Apple A7 in September 2013, furthermore, Qualcomm was facing anti-trust investigations in China, the European Union, and the United States. The combination of pressures caused a significant fall in Qualcomms profits. In July 2015, the company cut 4,700 jobs or about 15 percent of its 31,300 current workforce due to decline of sales, executive management knew this was coming so they came up with a plan to retain its employees. However, instead of paying reasonable salary, executive management used this plan as a justification to give themselves a big payout first and then lay off employees later. In December 2015, Qualcomm Inc. announced that it had rejected calls to split itself in two, deciding to keep its chipmaking and patent licensing businesses together
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LTE (telecommunication)
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In telecommunication, Long-Term Evolution is a standard for high-speed wireless communication for mobile phones and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements, the standard is developed by the 3GPP and is specified in its Release 8 document series, with minor enhancements described in Release 9. LTE is the path for carriers with both GSM/UMTS networks and CDMA2000 networks. The different LTE frequencies and bands used in different countries mean that only multi-band phones are able to use LTE in all countries where it is supported. LTE is commonly marketed as 4G LTE, but it does not meet the criteria of a 4G wireless service, as specified in the 3GPP Release 8 and 9 document series. The requirements were set forth by the ITU-R organization in the IMT Advanced specification. The LTE Advanced standard formally satisfies the ITU-R requirements to be considered IMT-Advanced, to differentiate LTE Advanced and WiMAX-Advanced from current 4G technologies, ITU has defined them as True 4G. LTE stands for Long Term Evolution and is a trademark owned by ETSI for the wireless data communications technology. However, other nations and companies do play an role in the LTE project. The goal of LTE was to increase the capacity and speed of data networks using new DSP techniques. A further goal was the redesign and simplification of the architecture to an IP-based system with significantly reduced transfer latency compared to the 3G architecture. The LTE wireless interface is incompatible with 2G and 3G networks, LTE was first proposed by NTT DoCoMo of Japan in 2004, and studies on the new standard officially commenced in 2005. Initially, CDMA operators planned to upgrade to rival standards called UMB and WiMAX, the evolution of LTE is LTE Advanced, which was standardized in March 2011. Services are expected to commence in 2013, additional evolution known as LTE Advanced Pro have been approved in year 2015. The LTE specification provides downlink peak rates of 300 Mbit/s, uplink peak rates of 75 Mbit/s, LTE has the ability to manage fast-moving mobiles and supports multi-cast and broadcast streams. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz, the simpler architecture results in lower operating costs. In 2004, NTT DoCoMo of Japan proposes LTE as the international standard, in September 2006, Siemens Networks showed in collaboration with Nomor Research the first live emulation of an LTE network to the media and investors. As live applications two users streaming an HDTV video in the downlink and playing a game in the uplink have been demonstrated
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Alcatel-Lucent
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Alcatel-Lucent S. A. was a French global telecommunications equipment company, headquartered in Boulogne-Billancourt, France. As of January 2016, the company is part of Nokia, the company focused on fixed, mobile and converged networking hardware, IP technologies, software and services, with operations in more than 130 countries. Alcatel-Lucents chief executive officer was Michel Combes and the chairman of the board was Philippe Camus. Camus joined the company in the quarter of 2008, alongside Ben Verwaayen as CEO, after Alcatel-Lucents first CEO Patricia Russo. For 2010, the company had revenues of €16 billion and a net loss of €334 million. For 2011, revenues were €15 billion, net loss of €1.1 billion, for 2012, revenues were €14.4 billion and net loss of €1.4 billion. On October 1,2014, it announced that it had closed the sale of its subsidiary Alcatel-Lucent Enterprise to China Huaxin Post & Telecommunication Economy Development Center, Alcatel-Lucent was formed when Alcatel merged with Lucent Technologies on December 1,2006. However, the predecessors of the company have been a part of industry since the late 19th century. The company has roots in two early telecommunications companies, La Compagnie Générale dElectricité and the Western Electric Manufacturing Company, Western Electric began in 1869 when Elisha Gray and Enos N. Barton started a manufacturing firm based in Cleveland, Ohio. By 1880, the company had relocated to Chicago, Illinois, CGE would become a leader in digital communications and would also be known for producing the TGV high-speed trains in France. Bell Telephone Laboratories was created in 1925 from the consolidation of the R&D organizations of Western Electric, Bell Labs researchers have won 7 Nobel Prizes. Also in 1925, Western Electric sold its International Western Electric Company subsidiary to ITT Corporation, CGE purchased the telecommunications part of ITT in the mid-1980s. AT&T re-entered the European telecommunications market in 1984 following the Bell System divestiture, Philips promoted the venture in part because its PRX public switching technology was ageing and it sought a partner to help fund the development costs of digital switching. In 1987, AT&T increased its holding to 60% and in 1990 it purchased the remainder of the Philips holding, in 1998, Alcatel Alsthom shifted its focus to the telecommunications industry, spinning off its Alsthom activities and changing the companys name to Alcatel. AT&T spun off Lucent Technologies in April 1996 with a public offering. In April 2004, TCL Corporation and Alcatel announced the creation of a mobile phone manufacturing joint venture, facing intense competition in the telecommunications industry, Alcatel and Lucent Technologies merged on November 30,2006. On April 5,2006, Alcatel announced that it would swap its shares of Alcatel Alenia Space and Telespazio for €673 million and a 12. 1% stake in Thales and this increased Alcatels stake in Thales to 20. 8%
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Cellular network
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A cellular network or mobile network is a communication network where the last link is wireless. The network is distributed over land areas called cells, each served by at least one fixed-location transceiver and this base station provides the cell with the network coverage which can be used for transmission of voice, data and others. A cell might use a different set of frequencies from neighboring cells, to avoid interference, when joined together these cells provide radio coverage over a wide geographic area. This allows mobile phones and mobile computing devices to be connected to the switched telephone network. Private cellular networks can be used for research or for large organizations and fleets, each of these cells is assigned with multiple frequencies which have corresponding radio base stations. The group of frequencies can be reused in other cells, provided that the frequencies are not reused in adjacent neighboring cells as that would cause co-channel interference. If there is a single transmitter, only one transmission can be used on any given frequency. Unfortunately, there is some level of interference from the signal from the other cells which use the same frequency. This means that, in a standard FDMA system, there must be at least a one cell gap between cells which reuse the same frequency, in the simple case of the taxi company, each radio had a manually operated channel selector knob to tune to different frequencies. As the drivers moved around, they would change from channel to channel, the drivers knew which frequency covered approximately what area. When they did not receive a signal from the transmitter, they would try other channels until they found one that worked, the taxi drivers would only speak one at a time, when invited by the base station operator. With TDMA, the transmitting and receiving time slots used by different users in each cell are different from each other, with FDMA, the transmitting and receiving frequencies used by different users in each cell are different from each other. In a simple system, the taxi driver manually tuned to a frequency of a chosen cell to obtain a strong signal. The principle of CDMA is more complex, but achieves the same result, time division multiple access is used in combination with either FDMA or CDMA in a number of systems to give multiple channels within the coverage area of a single cell. The key characteristic of a network is the ability to re-use frequencies to increase both coverage and capacity. The elements that determine frequency reuse are the distance and the reuse factor. The reuse distance, D is calculated as D = R3 N, cells may vary in radius from 1 to 30 kilometres. The boundaries of the cells can also overlap between adjacent cells and large cells can be divided into smaller cells, the frequency reuse factor is the rate at which the same frequency can be used in the network
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Mobile radio telephone
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Mobile radio telephone systems preceded modern cellular mobile telephony technology. Since they were the predecessors of the first generation of cellular telephones, technologies used in pre cellular systems included the Push to Talk, Mobile Telephone System, Improved Mobile Telephone Service, and Advanced Mobile Telephone System systems. These mobile telephones were usually mounted in cars or trucks, though briefcase models were also made, typically, the transceiver was mounted in the vehicle trunk and attached to the head mounted near the driver seat. They were sold through WCCs, RCCs, and two-way radio dealers, the A-Netz launched 1952 in West Germany as the countrys first public commercial mobile phone network. However it was manual and with little coverage for several decades. First automatic system was the Bell Systems IMTS which became available in 1964, offering automatic dialing to, altai mobile telephone system was launched into the experimental service in 1963 in USSR, becoming fully operational in 1965, a first automatic mobile phone system in Europe. The Televerket opened its first manual telephone system in Norway in 1966. Norway was later the first country in Europe to get a mobile telephone system. The service was provided from the 1960s until the 1980s when cellular AMPS systems made RCC equipment obsolete and these systems operated in a regulated environment in competition with the Bell Systems MTS and IMTS. RCCs handled telephone calls and were operated by companies and individuals. Some systems were designed to allow customers of adjacent RCCs to use their facilities, for example, the phone of an Omaha, Nebraska–based RCC service would not be likely to work in Phoenix, Arizona. Manual operation was often a fallback for RCC roamers, roaming was not encouraged, in part, because there was no centralized industry billing database for RCCs. For example, some systems used two-tone sequential paging to alert a mobile or hand-held that a phone was trying to call them. Some used a system called Secode 2805 which transmitted an interrupted 2805 Hz tone to alert mobiles of an offered call, some radio equipment used with RCC systems was half-duplex, push-to-talk equipment such as Motorola hand-helds or RCA 700-series conventional two-way radios. Other vehicular equipment had telephone handsets, rotary or pushbutton dials, a few users had full-duplex briefcase telephones. RCCs used paired UHF 454/459 MHz and VHF 152/158 MHz frequencies near those used by IMTS, using the same channel frequencies as IMTS, the US Federal Communications Commission authorized Rural Radiotelephone Service for fixed stations. List of mobile phone generations 1G 2G 3G 4G 5G Mobile rig Mobile radio Satellite telephone Mobile Phone History Mobile Phone Generations Storno. co. uk
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Radiotelephone
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A radiotelephone is a communications system for transmission of speech over radio. Radiotelephone systems are not necessarily interconnected with the land line telephone network. Radiotelephony means transmission of sound by radio, in contrast to radiotelegraphy or video transmission, the word phone has a long precedent beginning with early US wireless voice systems. The term means voice as opposed to telegraph or Morse code and this would include systems fitting into the category of two-way radio or one-way voice broadcasts such as coastal maritime weather. The term is popular in the amateur radio community and in US Federal Communications Commission regulations. A standard landline telephone allows both users to talk and listen simultaneously, effectively there are two channels between the two end-to-end users of the system. It is, however, the most comfortable method of communication for users. The most common method of working for radiotelephones is half-duplex, operation, which one person to talk. If a single channel is used, both take turns to transmit on it. An eavesdropper would hear both sides of the conversation, dual-frequency working splits the communication into two separate channels, but only one is used to transmit at a time. The end users have the experience as single frequency simplex. The user presses a switch on the transmitter when they wish to talk—this is called the press-to-talk switch or PTT. It is usually fitted on the side of the microphone or other obvious position, users may use a special code-word such as over to signal that they have finished transmitting, or it may follow from the conversation. Radiotelephones may operate at any frequency where they are licensed to do so and they may use simple modulation schemes such as AM or FM, or more complex techniques such as digital coding, spread spectrum, and so on. Licensing terms for a band will usually specify the type of modulation to be used. For example, airband radiotelephones used for air to ground communication between pilots and controllers operates in the VHF band from 118.0 to 136.975 MHz, Radiotelephone receivers are usually designed to a very high standard, and are usually of the double-conversion superhet design. Multiple channels are provided using a frequency synthesizer. Receivers usually features a squelch circuit to cut off the output from the receiver when there is no transmission to listen to
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Improved Mobile Telephone Service
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The Improved Mobile Telephone Service was a pre-cellular VHF/UHF radio system that links to the PSTN. IMTS was the equivalent of land dial phone service. It was introduced in 1964 as a replacement to Mobile Telephone Service or MTS, the original Bell System US and Canadian mobile telephone system includes three frequency bands, VHF Low, VHF High, and UHF. Alternative names were Low Band, High band and UHF, in addition to the Bell system channels, another 7 channels at VHF, and 12 channels at UHF were granted to non-wireline companies designated as RCCs. These RCC channels were adjacent to the Bell System frequencies, cellular networks remedied this problem by decreasing the area covered by one tower and increasing the number of cells. The disadvantage of this is more towers are required to cover a given area, thus, IMTS and MTS systems still exist in some remote areas, as it may be the only feasible way to cover a large sparsely-populated area. The basic operation of IMTS was very advanced for its time, in a given city, one IMTS base station channel was marked idle by the transmission of a steady 2000 Hz idle tone. Mobiles would scan the available frequencies and lock on to the channel transmitting the idle tone, any mobile recognizing that the call was for someone else would resume scanning for mark idle tone, while the called mobile would then transmit 2150 Hz guard tone back to the base station. When the mobile hung up, a burst of alternating 1336 disconnect and 1800 Hz seize tones would be sent to allow the station to service another call. Mobiles would originate calls by sending a burst of connect tone, digits are formed with a pulsetrain of alternating tones, either connect and silence or connect and guard. When the base received the calling partys identification, it would send dialtone to the mobile. The user would use the rotary dial, which would send the dialed digits as an alternating 10 pps pulse train of connect. Mobile installations normally consisted of a unit or the telephone handset which sat in a cradle with a direct dialing keyboard. These looked and functioned much like a landline, or hardwired, unlike cellular handsets, these units passed through a dial tone when the receiver was lifted from the cradle and in this way seemed more like a landline telephone than a cellular handset. There was a large radio transceiver chassis, typically measuring at least a foot square and 6 inches high. These transceivers were connected to the cradle with a multi-conductor cable usually around.5 inch thick. The antennas looked much like those used for CB radios and were about 19 in. long and these mobile telephone systems required a large amount of power and this was supplied by thick power cabling connected directly to the automobiles battery. Optionally these units were connected to the cars horn and were switched to honk the horn as a ringer when receiving an incoming call if the user was away from the car at the time of the call
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