2016 may be the first year of commercial use of uplink carrier aggregation
Currently, China Mobile and China Telecom’s Cat.6 (which is what operators call “4G+ ") network has been put into commercial use; China Unicom also officially launched "Wo 4G+" on December 8, 2015. So far, my country's operators have begun the "4G+" era.
While Chinese operators continue to deploy downlink carrier aggregation, they are also actively testing uplink carrier aggregation.
Recently, China Mobile carried out large-scale field tests of TD-LTE uplink carrier aggregation in five cities.
So what is the current development status of uplink carrier aggregation? Has the industrial chain matured? To this end, the reporter interviewed industry experts to answer questions for readers.
Uplink carrier aggregation benefits the entire industry chain
Reporter: What are the main technologies that can improve the network? Upwardrate? What are the advantages and disadvantages of each of these technologies?
Li Yang: Qualcomm currently mainly uses three technologies to improve network uplink speeds.
The first is carrier aggregation, which aggregates two or more frequency bands together to increase bandwidth and improve data transmission rates. Carrier aggregation can be applied to both downlink and uplink road.
At present, the industry generally deploys "4G+" networks that support Cat.6, and China Mobile has begun research and deployment of uplink carrier aggregation technology that supports Cat.7.
The second is 64-QAM high-order coding. Higher-order coding technology can allow the carrier to carry more information and also increase the upload rate.
The third is uplink data compression. Currently, uplink data compression technology is specifically designed for LTE networks and can achieve higher compression efficiency in certain application scenarios.
Upstream data compression can double the overall download speed of web pages, but it does not help much in application scenarios such as video transmission and image transmission.
64-QAM high-order coding has higher requirements for network quality and can generally be widely used in the center area of a cell. Once it reaches the edge of the cell, the network may automatically fall back to 16-QAM or lower order. Encoding to ensure communication.
However, 64-QAM high-order coding is not as effective as uplink carrier aggregation in terms of network rate improvement and network expansion.
Uplink carrier aggregation solves the basic problem of increasing the network uplink rate. On this basis, the other two technologies can be used in some application scenarios to provide users with a better experience.
Reporter: In your opinion, what application value can uplink carrier aggregation bring to operators?
Li Yang: Once operators complete the deployment of uplink carrier aggregation networks, they can provide users with faster network speeds and better experiences, thus increasing user stickiness.
At the same time, with the development of the entire ecosystem, each operator will be able to provide users with faster network speeds and better experiences. The overall data traffic of each user will continue to increase, which is very beneficial to the operator's business growth.
There is no doubt that uplink carrier aggregation can bring value to operators , and what I want to point out is that the increase in network uplink speed can benefit the entire mobile ecosystem.
The increase in network speed and the increase in software applications can improve the end-user experience in all aspects.
Currently, VR and AR technologies, games, etc. are developing rapidly, and software developers can also benefit from the increase in network uplink speeds.
China Mobile will The first to commercialize uplink carrier aggregation
Reporter: What are the realistic demands for uplink carrier aggregation? At present, the development of downlink carrier aggregation is relatively mature, and there are many operators around the world. Using downlink carrier aggregation technology, what is the global application of uplink carrier aggregation technology?
Yang Guang: The main market for uplink carrier aggregation is currently in China.
Among the major international operators, China Mobile is the only one that only operates TD-LTE networks. Other major operators either Operate LTEFDD, or LTEFDD with TD-LT E hybrid networking.
In LTEFDD or LTEFDD/TD-LTE hybrid networking mode, the uplink capabilities between operators are not very different, and the competition demand is not strong at present, while uplink carrier aggregation The high requirements on terminals also restrict the enthusiasm of operators to launch uplink carrier aggregation.
However, for TD-LTE operators, the uplink and downlink time slot ratio is generally 1:3, and the wireless resources allocated to the uplink are relatively limited, resulting in low uplink performance. LTEFDD is at a disadvantage in competition, so TD-LTE operators have strong incentives to deploy uplink carriers aggregation to improve its network uplink performance.
Currently, it seems that China Mobile will be the first mobile operator to commercialize uplink carrier aggregation.
With the development of its business, TD in other markets. -LTE operators also have a need to deploy uplink carrier aggregation.
In current mobile Internet applications, downlink traffic is generally higher than uplink traffic, and TD-LTE's asymmetric uplink and downlink time slot ratio can better adapt to this feature.
However, In certain specific scenarios, such as performances, sports competitions and other large-scale public events, users’ social sharing behavior will generateThere is a large amount of uplink traffic, and the ratio of uplink and downlink traffic is often close to 1:1, which places high demands on the uplink capability of the network.
On the other hand, two-way symmetric services such as VoLTE will also put certain requirements on the uplink capacity of the network.
Uplink carrier aggregation will enable the network to better support these services and application scenarios.
Li Yang: Some European and American operators have begun to actively test uplink carrier aggregation technology.
Compared with downlink carrier aggregation, uplink carrier aggregation networks are still in the early stages of commercial deployment, but the development of uplink carrier aggregation technology is now relatively mature and can enter the stage of commercial deployment.
Uplink carrier aggregation technology has matured
Reporter: What are the main methods and frequency bands that can be used for uplink carrier aggregation?
Yang Guang: Based on the current spectrum situation of China Mobile, uplink carrier aggregation is a more realistic realizationThe method is to implement Intra-Band carrier aggregation in the 2.6GHz frequency band, so that terminal implementation is relatively easy, and operators' network equipment upgrades and network planning optimization are also relatively simple.
Since China Mobile has abundant spectrum resources in the 2.6GHz band, there is currently no need for inter-band uplink carrier aggregation.
If cross-band uplink carrier aggregation is to be achieved, the primary challenge will be the implementation complexity of the terminal.
Reporter: Why can’t uplink carrier aggregation be as fast as downlink carrier aggregation? Is the current uplink carrier aggregation technology mature enough? Will you encounter any difficulties in specific applications?
Yang Guang: Due to the limitations of terminal conditions such as the number of antennas, transmit power, component size, power consumption, etc., in mobile communication systems, the performance of the uplink has always been weaker than that of the downlink, but this is also consistent with Due to the asymmetric nature of mobile Internet traffic, except for some special cases mentioned above, in most cases, uplink performance is not a bottleneck that affects user experience.
To achieve uplink carrier aggregation, the complexity of baseband chips and radio frequency circuits will increase, and R&D, production and testing costs will also increase accordingly.
In specific applications, the design of terminals and chips will be the biggest challenge that uplink carrier aggregation needs to face.
Li Yang: LTE has two standards: LTEFDD and TD-LTE.
LTEFDD is a frequency division mode. The current default downlink encoding format is 64-QAM, which can be increased to 256-QAM or even higher in the future.
Downlink signals are mainly transmitted from base stations, and there is no need to consider power consumption and mobility issues, so high-order coding can be used to achieve better coverage.
The uplink signal is mainly transmitted from mobile terminals. Mobile terminals are limited by battery life and must be within a safe range for human radiation.
Therefore, the transmit power, coverage, and coding format of the uplink signal are lower than those of the downlink signal. This is one of the reasons for the difference in uplink and downlink rates.
For TD-LTE, in addition to the coding format, transmit power, coverage and other factors just mentioned, it is also affected by time slot allocation.
If the network uplink transmission time slot is short, the uplink network speed will be affected, which is also the reason for the difference in uplink and downlink speeds.
The development of uplink carrier aggregation technology has been relatively mature.
China Mobile’s field test of uplink carrier aggregation has passed all test items. From a chip perspective, Qualcomm’s chips equipped with Snapdragon X12 modem have begun mass production.
The maturity of uplink carrier aggregation terminals, network equipment, and chips has reached the level of commercial use.
2Uplink carrier aggregation may enter a period of rapid development in the second half of 016
Reporter: What plans does Qualcomm have to promote the development of uplink carrier aggregation?
Li Yang: The maturity of a technology requires not only the maturity of the chip, but also the cooperation of the entire industry chain.
Qualcomm cooperates very closely with the industry chain and is making every effort to promote the maturity of uplink carrier aggregation technology from the terminal side of the ecosystem.
Currently, Qualcomm's most high-end modems are already installed on the Snapdragon 800 series platform. The Snapdragon 820 is equipped with the most advanced Snapdragon X12 modem, supporting Cat.13 uplink transmission rates up to 150Mbit/s.
In addition to the X12 modem, the X8 modem layer can support LTECat.7 uplink carrier aggregation and has been integrated into the Snapdragon 652, Snapdragon 650 and Snapdragon 617 processors.
Reporter: Based on ChinaChinese operators, led by China Mobile, are constantly promoting the commercialization of uplink carrier aggregation. In your opinion, when is it expected that uplink carrier aggregation will be commercially available? When will the large-scale deployment period begin again?
Yang Guang: Under the pressure of market competition, China Mobile has great motivation to promote the development of uplink carrier aggregation.
To achieve uplink carrier aggregation, network equipment first needs to be upgraded, and support from terminal equipment is also required.
With the launch of new chips from Qualcomm, Samsung, Huawei HiSilicon and other manufacturers, it is expected that terminals supporting uplink carrier aggregation will appear on the market in 2016, making the commercial use of uplink carrier aggregation possible.
In the second half of 2016, uplink carrier aggregation may enter a period of rapid development.
