CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The name CDMA2000 actually denotes a family of standards that represent the successive, evolutionary stages of the underlying technology. These are, in order of evolution: CDMA2000 1xRTT CDMA2000 1xEV-DO: Release 0, Revision A, Revision B CDMA2000 1xEV-DO Revision C or Ultra Mobile Broadband (UMB) CDMA2000 1xEVDVAll are approved radio interfaces for the ITU's IMT-2000. CDMA2000 has a relatively long technical history and is backward-compatible with its previous 2G iteration IS-95 (cdmaOne). In the United States, CDMA2000 is a registered trademark of the Telecommunications Industry Association (TIA-USA).Contents 1 1X 2 1xEV-DO 3 1X Advanced 4 Networks 5 History 6 References 7 External links1XCDMA2000 1X (IS-2000), also known as 1x and 1xRTT, is the core CDMA2000 wireless air interface standard. The designation "1x", meaning 1 times Radio Transmission Technology, indicates the same radio frequency (RF) bandwidth as IS-95: a duplex pair of 1.25 MHz radio channels. 1xRTT almost doubles the capacity of IS-95 by adding 64 more traffic channels to the forward link, orthogonal to (in quadrature with) the original set of 64. The 1X standard supports packet data speeds of up to 153 kbit/s with real world data transmission averaging 80–100 kbit/s in most commercial applications. IMT-2000 also made changes to the data link layer for greater use of data services, including medium and link access control protocols and QoS. The IS-95 data link layer only provided "best efforts delivery" for data and circuit switched channel for voice (i.e., a voice frame once every 20 ms). 1xEV-DO Main article: Evolution-Data Only BlackBerry smartphone displaying '1XEV' as the service status in the upper right corner.CDMA2000 1xEV-DO (Evolution-Data Only), often abbreviated as EV-DO or EV, is a telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. It uses multiplexing techniques including code division multiple access (CDMA) as well as time division multiple access (TDMA) to maximize both individual user's throughput and the overall system throughput. It is standardized by 3rd Generation Partnership Project 2 (3GPP2) as 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. 1X Advanced1X Advanced is the evolution of CDMA2000 1X. It provides up to four times the capacity and 70% more coverage compared to 1X. Networks See also: List of CDMA2000 networksThe CDMA Development Group states that, as of May 2012, there are 329 operators in 121 countries offering CDMA2000 1X and/or 1xEV-DO service. HistoryThe intended 4G successor to CDMA2000 was UMB (Ultra Mobile Broadband); however, in November 2008, Qualcomm announced it was ending development of the technology, favoring LTE instead.
Seán Mac Diarmada and CDMA2000"Sean MacDermott" redirects here. For other uses, see Sean McDermott (disambiguation).Seán Mac Diarmada (English: John MacDermott; 28 February 1883 – 12 May 1916), also known as Seán MacDermott, was an Irish political activist and revolutionary leader. He was one of the seven leaders of the Easter Rising of 1916, which he helped to organise as a member of the Military Committee of the Irish Republican Brotherhood (IRB) and was a signatory of the Proclamation of the Irish Republic. He was executed for his part in the Rising at the age of thirty-three.Raised in rural County Leitrim, he was a member of many associations which promoted the cause of the Irish language, Gaelic revival and Irish nationalism in general, including the Gaelic League and (early in his career) the Catholic fraternity the Ancient Order of Hibernians. He was national organiser for Sinn Féin, and later manager of the newspaper Irish Freedom, started in 1910 by Bulmer Hobson and others. Within the Irish Republican Brotherhood, he was a close colleague and friend of veteran republican Tom Clarke.Contents 1 Early life 2 Easter Rising 3 Commemoration 4 See also 5 References 6 External linksEarly lifeMac Diarmada was born in Corranmore, close to Kiltyclogher in County Leitrim, an area where the landscape was marked by reminders of poverty and oppression.Surrounding Mac Diarmada in rural Corranmore, north Leitrim, there were signs of Irish history throughout the area. There was an ancient sweat-house, Mass rocks from the penal times and the persecutions of the 17th and 18th centuries, and deserted abodes as an aftermath of the hunger of the 1840s. He was educated by the Irish Christian Brothers. In 1908 he moved to Dublin, by which time he already had a long involvement in several Irish separatist and cultural organisations, including Sinn Féin, the Irish Republican Brotherhood (IRB), the Ancient Order of Hibernians and the Gaelic League. He was soon promoted to the Supreme Council of the IRB and eventually elected secretary.In 1910 he became manager of the radical newspaper Irish Freedom, which he founded along with Bulmer Hobson and Denis McCullough. He also became a national organiser for the IRB, and was taken under the wing of veteran Fenian Tom Clarke. Indeed over the year the two became nearly inseparable. Shortly thereafter Mac Diarmada was stricken with polio and forced to walk with a cane.In November 1913 Mac Diarmada was one of the original members of the Irish Volunteers, and continued to work to bring that organisation under IRB control. In May 1915 Mac Diarmada was arrested in Tuam, County Galway, under the Defense of the Realm Act for giving a speech against enlisting into the British Army. Easter Rising Plaque outside offices in Dublin once used by Seán MacDiarmadaFollowing his release in September 1915, he joined the secret Military Committee of the IRB, which was responsible for planning the rising. Indeed Mac Diarmada and Clarke were the people most responsible for it.Due to his disability, Mac Diarmada took little part in the fighting of Easter week, but was stationed at the headquarters in the General Post Office. Following the surrender, he nearly escaped execution by blending in with the large body of prisoners. He was eventually recognised by Daniel Hoey of G Division. Following a court-martial on 9 May, Mac Diarmada was executed by firing squad on 12 May at the age of 33. In September 1919 Hoey was shot dead by Michael Collins's Squad. Likewise, the British Officer Lee-Wilson, who ordered Mac Diarmada to be shot, rather than imprisoned, was also killed in Cork on Collins's order during the Irish War of Independence.Before his execution, Mac Diarmada wrote, "I feel happiness the like of which I have never experienced. I die that the Irish nation might live!”. CommemorationSeán MacDermott Street in Dublin is named in his honour. So too is Mac Diarmada rail station in Sligo, and Páirc Sheáin Mhic Dhiarmada, the Gaelic Athletic Association stadium in Carrick-on-Shannon. Sean MacDermott tower in Ballymun, demolished in 2005, was also named after him. In his hometown of Kiltyclogher a statue enscribed with his final written words – see above – was erected in the village centre, his childhood home has become a National Monument. See also List of people on stamps of Ireland
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