What is LTE in mobile phones?( advantages & disadvantages) 2012
LTE (Long Term Evolution) is a standard for wireless communication of high-speed data for mobile phones and data terminals which is marketed as 4G LTE.It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using new modulation techniques.
LTE uses radio waves to allow more data to be transferred over the same bandwidth used by 3G equipment. As a result, service providers should be able to get more data transfer out of their existing cells and possibly lower the cost to run their networks. Since LTE connects to existing networks, providers can plan for a seamless transition, then continue to use legacy CDMA and GSM networks as backups.
From History to 2013
LTE was first proposed by NTT DoCoMo of Japan in 2004, and studies on the new standard officially commenced in 2005. In May 2007, the LTE/SAE Trial Initiative (LSTI) alliance was founded as a global collaboration between vendors and operators with the goal of verifying and promoting the new standard in order to ensure the global introduction of the technology as quickly as possible. The LTE standard was finalized in December 2008, and the first publicly available LTE service was launched by TeliaSonera in Oslo and Stockholm on December 14, 2009 as a data connection with a USB modem. In 2011, LTE services were launched by major North American carriers as well, with the Samsung Galaxy Indulge offered by MetroPCS starting on February 10, 2011 being the first commercially available LTE smartphone and HTC ThunderBolt offered by Verizon starting on March 17 being the second LTE smartphone to be sold commercially. Initially, CDMA operators planned to upgrade to a rival standard called the UMB, but all the major CDMA operators (such as Verizon, Sprint and MetroPCS in the United States, Bell and Telus in Canada, au by KDDI in Japan, SK Telecom in South Korea and China Telecom/China Unicom in China) have announced that they intend to migrate to LTE after all. The evolution of LTE is LTE Advanced, which was standardized in March 2011. Services are expected to commence in 2013.
- Peak download rates up to 299.6 Mbit/s and upload rates up to 75.4 Mbit/s
- Improved support for mobility, exemplified by support for terminals moving at up to 350 km/h or 500 km/h depending on the frequency band.
- Increased spectrum flexibility: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz wide cells are standardized.
- Upports at least 200 active data clients in every 5 MHz cell.
- Support for cell sizes from tens of metres radius (femto and picocells) up to 100 km radius macrocells. In the lower frequency bands to be used in rural areas, 5 km is the optimal cell size, 30 km having reasonable performance, and up to 100 km cell sizes supported with acceptable performance. In city and urban areas, higher frequency bands (such as 2.6 GHz in EU) are used to support high speed mobile broadband. In this case, cell sizes may be 1 km or even less
- Users can start a call or transfer of data in an area using an LTE standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS or even 3GPP2 networks such as cdmaOne or CDMA2000)
- VOICE CALLS:The LTE standard only supports packet switching with its all-IP network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to re-engineer their voice call network.
- FREQUWNCY BAND:The LTE standard can be used with many different frequency bands. In North America, 700/ 800 and 1700/ 1900 MHz are planned to be used; 800, 1800, 2600 MHz in Europe; 1800 and 2600 MHz in Asia; and 1800 MHz in Australia.As a result, phones from one country may not work in other countries. Users will need a multi-band capable phone for roaming internationally.
- LTE has adopted multiple-input multiple-output (MIMO) technology. As a result, cell basestations may need additional transmit and receive antennae. Mobile phones may have one transmit antenna and up to two receive antennae. Service providers may have to upgrade basestations, and consumers will need to buy new phones to utilize these upgraded networks.