Skytel -, Mongolia
Skytel is Mongolia's largest CDMA mobile telecoms network provider. In a country of 2.43 million people living in 1.5 million km² of open space, subscriber numbers are immaterial. Good coverage in the populated areas is important. In Mongolia, there are approximately 110,000 cellular subscribers and 3,300 paging subscribers (2001 figures). KDD, Sumitomo Corporation of Japan in a joint venture with Mongolian Newcom Co Ltd deployed the first mobile telephone network in Ulaanbaatar, which started operations in March 1996.
Skytel was a joint venture company (JVC) selected through international competitive bidding for deployment of a mobile network. Skytel was established by Univcom Co Ltd (Mongolia), SK Telecom Co Ltd (Republic of Korea) and Taihan Electric Wire Co Ltd (Republic of Korea) in April 1999. Skytel (backed by SK Telecom of Korea) began offering the nation's first CDMA cellular service in February 2001 and a WAP-based wireless portal service in April 2004. Subscriber numbers have risen since then.
CDMA NETWORK ENHANCEMENT
ZTE Corporation signed a key contract in June 2006 to provide Skytel with the world's first commercial CDMA 2000 EV-DO Rev A network. CDMA 2000 1xEV-DO Rev A is the first commercially-developed technology to enable high quality wireless Voice over Internet Protocol (VoIP). Using session initiation protocol (SIP), it is said to achieve VoIP calls which are potentially of the same quality as public switched telephone network (PSTN) calls.
This is actually an enhanced version of 1xEV-DO Release 0, a broadband wireless technology which is already deployed on CDMA networks across the world (including Skytel's current network). Rev A is said to improve data rates, Quality of Service (QoS) and network capacity. Using this technology, service providers can deliver IP-based applications and services such as video messaging and large file upload.
Rev A is also a key enabler for delay-sensitive services, such as push-to-talk and Instant Multimedia Messaging (IMM), as well as integrated voice and data services, such as video telephony. This contract marks the first successful deployment of CDMA 2000 solutions with EV-DO Rev A for commercial use globally. The upgraded network is expected to be complete by the end of Q3 2006. The new network will serve subscribers in a number of Mongolia's major cities including Darkhan, Erdenet and the capital Ulan Bator.
Capable of enabling uplink speeds of up to 1.8Mbps and downlink speeds of 3.1Mbps (compared with EV-DO Rev 0's respective 153.6kbps and 2.4Mbps), the new network will support a wide variety of data rich multimedia applications. Skytel's network will be enhanced by adding EV-DO Rev A channel modules to its existing CDMA 2000 1X network. This means there will be no need to change to the RF modules or the antenna feeder system.
REV A AND REV B
Rev A offers fast packet establishment on both the forward and reverse links along with air interface enhancements that reduce latency and improve data rates. In addition to the increase in the maximum downlink (forward link) data rate from 2.4576Mb/s in Rev 0 to 3.1Mb/s, Rev A has a 12-times improvement in the maximum uplink (reverse link) data rate, from .15Mb/s to 1.8Mb/s. EV-DO Rev A supports low latency services including VoIP and video telephony on the same carrier with traditional Internet packet data services.
The air-interface latency specifications give latency in the ‘low double digit’ with the highest RSVP settings. This compares favourably with Release 0 air-interface latencies of 150–200ms. In the meantime, 3GPP2, the CDMA 2000 standards organisation has started developing 1xEV-DO Rev B or NxEV-DO, a standard that enables 1xEV-DO to deliver higher peak rates using multiple 1.25MHz channels (so three 1.25MHz channels would mean 3×3.1Mbps, which is 9.3Mbps).