What are the advantages of the newly emerging LTE-A?

SK Telecom's fifth-generation communication network technology is called "tri-band Long Term Evolution-Advanced" (LTE-A), which is the next generation network of the fourth-generation communication network "Long Term Evolution" (LTE).

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While the country is still arguing over the issue of when FDD licenses will be issued, Smecta has amazed the world with its Internet speed.

Recently, South Korean telecom operator SK Telecom announced the official launch of tri-band LTE-A commercial use. At the same time, Samsung officially released the first smartphone supporting LTE-A Tri-Band CA: Galaxy Note 4 LTE-A. In fact, as early as January this year, SK Telecom announced the successful development of the world's first "LTE-A tri-band carrier aggregation" technology. The Galaxy Note 4 LTE-A released this time is equipped with Qualcomm's latest 64-bit Snapdragon 810 processor and integrated LTE-A Cat.9 modem, marking that the corresponding chipsets and devices for tri-band LTE-A commercial use have matured.

Prior to this, carrier aggregation had been achieved in two frequency bands. Hong Kong Mobile Communications (CSL) achieved the highest 20MHz+20MHz in September last year. The Koreans achieved three-band carrier aggregation for the first time, 20MHz+10MHz+10MHz to be exact. Although the total number of frequency bands seems similar and the theoretical maximum download rate has reached 300Mbps (according to calculations, it only takes 19 seconds to download a 1GB movie), three-band carrier aggregation represents a more complex technological breakthrough.

Technical Features of LTE-A

What is LTE-A? Some reports call SK Telecom's current commercial tri-band LTE-A the fifth generation of communications, which is actually a misunderstanding of LTE-A and LTE.

Strictly speaking, LTE-A is a further evolution of LTE technology. At the Quebec meeting in November 2004, 3GPP determined the Long Term Evolution plan for 3G systems, which later became widely known as LTE. In March 2008, the International Telecommunication Union (ITU) basically completed the standardization of LTE. The first two versions of LTE, Release 8 and Release 9, did not meet the ITU's peak requirement of 1Gbit/s for 4G, and were generally called 3.9G or quasi-4G. After that, LTE R10, which was launched on the basis of R8/R9, integrated a new technical architecture and truly met the peak rate requirements of ITU. LTE R10 and subsequent versions are called LTE-Advanced (LTE-A), which can be regarded as true 4G. In January 2012, ITU approved LTE-A as one of the 4G technologies, and LTE R12 is currently undergoing standard certification.

LTE-A is not an independent technology, but a technology set consisting of a series of enhanced features in R10 and subsequent versions of the standard, such as carrier aggregation, high-order MIMO, enhanced inter-cell interference coordination, and relay.

1. Carrier aggregation

Spectrum resources are always limited, especially in a market environment with a surge in network traffic. To achieve the high peak requirements of LTE-A, the most direct way is to increase the transmission bandwidth. Carrier aggregation aims to aggregate multiple continuous or discrete narrow bandwidth carriers to form a wider complete spectrum, which not only meets the higher system bandwidth requirements of the LTE-A system, but also effectively utilizes fragmented spectrum resources.

Everyone is bragging: What other benefits does LTE-A have besides being fast?

LTE uses OFDM multiple access technology to convert high-speed data streams into serial-to-parallel data streams and allocate frequency resources in units of subcarriers. According to the number of subcarriers, it can support various system bandwidths of 1.4, 3, 5, 10, 15 and 20 MHz, and the maximum transmission bandwidth is 20 MHz. LTE-A aggregates multiple backward-compatible LTE carriers and supports up to 5 carriers to aggregate at the same time, achieving a transmission bandwidth of 100 MHz. LTE-A terminal equipment can access multiple carriers or access one LTE carrier normally for operation.

It can be said that carrier aggregation is the basis for the large bandwidth operation of LTE-A system, and is an important component and focus of LTE-A. For operators, carrier aggregation technology determines whether they can achieve "peak rate advantage". SK Telecom's tri-band LTE-A can be understood as the simultaneous aggregation of three LTE carriers.

2. High-order MIMO

High-order MIMO technology is another key technology for improving the throughput of LTE systems and is also one of the representative technologies of 4G. Without increasing the bandwidth, the capacity and spectrum utilization of the communication system can be multiplied by using multiple antennas at the transmitting and receiving ends. Release 8 can support the parallel transmission of up to 4 data streams, and achieve a peak rate of more than 300Mbit/s at a bandwidth of 20MHz. LTE-A downlink transmission is extended from 4 antennas in LTE to 8 antennas, supporting the transmission of up to 8 layers and two codeword streams. R10 and R11, which were completed in 2011 and 2012 respectively, can increase the downlink peak rate to 3Gbit/s and the downlink peak spectrum efficiency to 30bit/s/Hz.

3. Wireless relay technology

Traditional base stations need to provide wired links on the site for "backhaul transmission", while relay stations use wireless links to perform backhaul transmission on the network side. They are small in size, light in weight, and easy to site. With the help of relay forwarding by relay stations, the network coverage can be expanded to areas outside the cell and other coverage blind spots. At the same time, by reducing the propagation distance of the signal, the data throughput in hot spots can be effectively improved to ensure network quality.

The LTE-A trend is coming

The LTE-A tri-band carrier aggregation technology launched by South Korea has opened up a surging LTE-A trend for domestic people who have not yet figured out the difference between TDD and FDD.

LTE users have shown a huge data traffic consumption capacity. Data shows that in the first four months of 2014, the average data usage of LTE users in Hong Kong was almost twice that of 3G users. In July 2013, the US operator Verizon announced that 57% of the mobile data traffic in the network was transmitted by LTE. The mining of 4G users' data traffic consumption is highly consistent with the operators' response to the "pipeline" crisis.

But another embarrassing fact for operators is that WiFi still plays an important role in meeting the rapidly increasing data needs of users. In all major LTE markets, WiFi data still accounts for 75%-90% of the total mobile data. In other words, users' data needs are increasing rapidly, but the 4G network with greatly increased capacity has not fully demonstrated its diversion effect in handling large data traffic in most cases.

Let's use the example of high-speed rail to better understand the situation. After a long period of hype, it was discovered that everyone chose to take the bullet train, or choose to fly for long-distance travel. With the advancement of high-speed rail technology, high-speed rail decided to launch long-distance sleeper high-speed rail and intercity high-speed rail.

With the accelerated commercialization of LTE-A and the technical cost advantages, LTE-A network deployment was strongly promoted by operators in 2014. According to GSA statistics, as of October 2014, 21 operators in 14 countries around the world have launched LTE-A commercial networks based on carrier aggregation technology, including Japan, South Korea, the United States, France, etc., and more than 79 operators are carrying out network deployment or trials.

The pace of LTE-A commercialization, led by Hong Kong and South Korea, has been gradually accelerating recently. As the country that has been most aggressive in promoting LTE-A commercial networks, South Korea's three major operators have all launched LTE-A services based on carrier aggregation. The country already has nearly 210,000 LTE-A base stations, accounting for 47% of the number of LTE base stations (nearly half of the LTE base stations have been upgraded to LTE-A base stations!). In December 2014, Singapore's telecommunications operators M1 and SingTel announced the launch of commercial LTE-A networks, promising that all 4G customers with compatible devices will be able to use LTE-A services without paying extra; Telstra announced the launch of LTE-A commercial services; at the same time, Saudi Arabian operator STC launched the world's only TDD LTE-A network.

The LTE-A network is coming at you like a rocket. It's time to hold on tight, and hold on to your wallet tight.

As a winner of Toutiao's Qingyun Plan and Baijiahao's Bai+ Plan, the 2019 Baidu Digital Author of the Year, the Baijiahao's Most Popular Author in the Technology Field, the 2019 Sogou Technology and Culture Author, and the 2021 Baijiahao Quarterly Influential Creator, he has won many awards, including the 2013 Sohu Best Industry Media Person, the 2015 China New Media Entrepreneurship Competition Beijing Third Place, the 2015 Guangmang Experience Award, the 2015 China New Media Entrepreneurship Competition Finals Third Place, and the 2018 Baidu Dynamic Annual Powerful Celebrity.