"From Gigabit LTE technology to 5g and then to LTE layout for the Internet of things, what is Qualcomm's next game?
In the field of mobile communications, Qualcomm has always been at the forefront of the industry. At the media salon recently held at Qualcomm innovation center in Shenzhen, Shen Lei, product marketing director of Qualcomm wireless semiconductor technology Co., Ltd. Shanghai Branch, not only introduced in detail the world's first 5g modem Xiaolong X50 announced last month and the Gigabit LTE modem Xiaolong x16 launched in February this year, but also revealed its LTE layout for the Internet of things. From Gigabit LTE technology to 5g and then to LTE layout for the Internet of things, what kind of chess is Qualcomm playing?
How is the Gigabit LTE modem Xiaolong x16 refined?
Not long ago, Netgear launched the world's first Gigabit LTE mobile terminal - mobile router mr1100, and Telstra's new Gigabit LTE network supported by Ericsson, which is based on Xiaolong x16 modem and Qualcomm ® Wi Fi solutions.
"Gigabit rate is the rate of optical fiber, which can be said to be a high benchmark in the wireless field." Shen Lei, product marketing director of Qualcomm wireless semiconductor technology Co., Ltd. Shanghai Branch, said that Gigabit rate is actually achieved by the integration of a variety of technologies, including carrier aggregation, high-order modulation and higher-order MIMO.
The basis of Gigabit LTE is carrier aggregation. The carrier must have a bandwidth of at least 20MHz“ In the past, GSM was 200kHz, WCDMA and HSPA + were 5MHz, while LTE had at least one carrier 20MHz. " Shen Lei said that on this basis, the modulation mode of LTE has also been upgraded compared with 2G and 3G. The initial downlink modulation mode is 64-QAM, and a wireless signal can transmit 6 bits. In addition, MIMO is required for LTE from the original cat. 4 up to the standard. The threshold is 2x2mimo, which means that there should be two antennas and two RF channels at the receiving end. In short, there are two data streams.
Compared with high-order modulation and higher-order MIMO, carrier aggregation is the easiest to implement and the first to be adopted. Taking the Telstra scenario as an example, Shen Lei said that Telstra has three authorized frequency bands, each of which is 20MHz. It can aggregate the three carriers or the three frequency bands through RF and baseband technology, that is, turn the three RF channels into a wider channel, that is, 3 × 20MHz, actually 60MHz. Each carrier has 2 data streams, and there are 6 data streams under the condition of three carriers. A data stream is 64-QAM with a speed of 75mbps. 75Mbps × 6 = 450mbps, so the bandwidth of 450mbps can be obtained by three carrier aggregation. This is one of the technologies to achieve Gigabit. The speed can be increased to 450mbps through three carrier aggregation.
The second is the enhanced modulation scheme, downlink 256-qam. By increasing the complexity of the transceiver, a signal can carry more bits. 256-qam is a signal that can carry 8 bits, which is 33% higher than that of the previous 64-QAM“ A data stream is increased by 33% from the original 75mbps to 100Mbps. There are six streams in three carrier aggregation. There are 100Mbps on one data stream through 256-qam, so it becomes 100Mbps × 6, up to 600mbps. " Shen Lei explained that this is achieved through three carrier aggregation and 256-qam.
Third, deploy 4x4 MIMO. This means deploying higher-order MIMO, more antennas, more transceiver links and more data streams on the terminal. Shen Lei still took the deployment of Telstra as an example to explain that it deployed 4 on two carriers × 4mimio, the remaining carrier is still 2 × 2MIMIO。 After using 4x4mimio technology, the number of data streams on one carrier changes from 2 to 4. The three carriers under this deployment are 4 + 4 + 2 and 10 data streams. Under the condition of 256-qam, a data stream is 100Mbps, so 100Mbps × 10 to 1Gbps.
"Through the above three main technologies, we can achieve 1Gbps." Shen Lei said that the reason why all three carriers do not use 4x4mimio is a trade-off result of system complexity. At this stage, the industry can support the best technology and can achieve up to 10 data streams. Although it will evolve later, it is the limit of x16 modem to achieve 10 data streams“ However, Qualcomm is already planning future products. The data flow will definitely increase. In the future, there will be 12 or even 15 data flows. "
In fact, there are still several difficulties to be overcome in 4x4 MIMO technology. Shen Lei, for example, said that the reference point of LTE requires two antennas, that is, at least 2x2mimo. Now the mobile phone is getting thinner and thinner, but the battery, application processor and camera module are getting larger and larger, leaving less and less space for the antenna. Moreover, the technical shell of the mobile phone will hinder the antenna performance, and the antenna performance is actually declining. 2x2mimo has a certain challenge in R & D. If you do 4x4 MIMO, you need four links and four sets of antennas, which is more difficult. However, Shen Lei also pointed out that some of the world's leading manufacturers have now conquered the technology of making four antennas in lightweight mobile phones. For example, Samsung Galaxy S7 / S7 edge facing North America T-Mobile is 4x4 MIMO, and Sony Xperia XZ, which are all based on Xiaolong 820 processor. There are also many manufacturers in China to make efforts in this regard. I believe that a large number of manufacturers can overcome this difficulty in the near future.
"Qualcomm's Xiaolong x16 modem is very flexible, but its capability is to do four carrier aggregation at most and 10 data streams at most, which is the highest capability in the industry and the fastest wireless connection at present." Shen Lei said that in fact, after 1Gbps, each operator can flexibly deploy carriers according to the assets of its own frequency band. One can be 700MHz, one can be 900MHz and one can be 1.8GHz. Some carriers can be TDD and some carriers can be FDD, which can be mixed and aggregated together. In addition, thanks to the support of LAA and lte-u, reducing the number of licensed spectrum required - which can be reduced to 40 MHz or less - will significantly increase the number of operators that can deploy Gigabit LTE rate networks around the world.
It is reported that Xiaolong x16 LTE modem is integrated into Xiaolong 835 processor just released by Qualcomm.
Shen Lei said that thanks to the Gigabit LTE speed of Xiaolong x16 LTE modem, users will be able to enjoy the advantages brought by its breakthrough functions, such as real-time transmission of 360 degree virtual reality content, new audio-visual entertainment experience (fast cache ultra-high fidelity music and movies), real-time app application (you can enjoy it without downloading and installing) Faster and more seamless access to cloud applications and services. At the same time, cloud storage may have a reading speed comparable to that of local flash memory“ In the development process from 2G to 3G to 4G, every time the wireless communication bandwidth rate increases, the subsequent applications and services will soon keep up. I believe that when the data rate reaches above 1g, the deployment and services of operators will be completed, and the application and service developers will have a lot of ideas to let everyone experience the new mobile broadband experience. "
The first 5g modem X50 was launched to accelerate the development of 5g global standard 5g Nr
In addition to the Gigabit LTE modem, Shen Lei also introduced in detail the 5g modem X50 released by Qualcomm at the 4G / 5G summit in Hong Kong. This is also the industry's first 5g modem product.
snapdragon ™ X50 is designed to support OEMs to build next-generation cellular terminals and assist operators in early 5g testing and deployment. Shen Lei pointed out that the 5g frequency band is still under discussion, and the 3GPP organization is still developing specifications for all levels of the whole 5g, such as terminal access network, core network, and from physical layer to link layer to application layer. Therefore, it will take some time to see a global standard emerge“ Then, the emergence of X50 5g modem is mainly aimed at the early deployment of operators before the emergence of 3GPP standard, such as Verizon's 5g TF and Korea Telecom's 5g-sig specification, both of which are 28ghz millimeter waves. "
Xiaolong X50 5g modem will initially support the operation of millimeter wave spectrum in 28ghz band. It adopts multiple input multiple output (MIMO) antenna technology supporting adaptive beamforming and beam tracking technology to realize stable and continuous mobile broadband communication in non line of sight (NLOS) environment. By supporting 800MHz bandwidth, Xiaolong X50 5g modem is designed to support peak download speeds of up to 5 gigabits per second. This is five times higher than 1Gbps Gigabit LTE.
In addition, the X50 supports dual connected multimode 4G / 5G“ Xiaolong X50 5g modem can be connected with Qualcomm with integrated Gigabit LTE modem ® snapdragon ™ Processor matching and close coordination through dual connectivity can be used for 4G / 5G multimode mobile broadband and fixed wireless broadband terminals. "
Shen Lei further explained that carrier aggregation is one of the most important technologies to realize Gigabit LTE, which is more obvious on 5g. 5g supports low-frequency bands below 6GHz. The authorized band is up to 3.5G, and the unauthorized band is about 5GHz. These bands are relatively low, so the bandwidth is relatively limited and discrete. The frequency bands used by each operator, country and region are also different. This is because in the development process from 2G to 3G, many frequency bands are occupied, and many are taken out for other applications. Therefore, among the frequency bands that can be found, the frequency bands used by various countries are different and relatively discrete.
In the frequency band below 6GHz, Xiaolong x16 LTE modem can flexibly aggregate the four carriers according to different situations, whether the carriers are in the authorized frequency band or the unauthorized frequency band. In the 4G era, it aggregates up to four carriers and up to 10 data streams. In the 5g era, take Xiaolong X50 modem as an example. It supports the high frequency band of 28ghz. After the frequency band is high, the bandwidth will increase significantly. Then in the millimeter wave band, it will have a bandwidth of hundreds of megabytes or even gigabytes“ The wider the bandwidth, the more data can be transported per unit time. Xiaolong X50 5g modem operates in the 28ghz band. It can aggregate eight carriers in this band. Each carrier supports 100MHz bandwidth, that is, 800MHz bandwidth, so as to significantly improve the data transmission capacity. The data transmission rate is from Gigabit to 5Gbps, which is the most important factor. "
Why explore the deployment of millimeter wave from the 6GHz band in the 2G and 3G era? Shen Lei said this is because there is still higher spectrum to use. With the improvement of frequency band, the bandwidth becomes wider and wider, and more and more data are transmitted, so as to improve the transmission rate“ Millimeter wave is an electromagnetic wave whose wavelength is in the order of millimeter. Now it is broadly defined that the frequency above 24GHz can be called millimeter wave. 5g now intends to deploy at several points in the 24GHz to 100GHz band, such as near 24GHz, near 60GHz and near 75ghz. Of course, it still needs a lot of negotiation and preparation between the International Telecommunication Union and 3GPP, but it is very possible to deploy 5g on millimeter wave. " Shen Lei believes that "5g can use millimeter wave, but it is not necessary to use millimeter wave. 5g is the pursuit of enhanced mobile broadband, massive Internet of things deployment and low latency of key business services. "
Shen Lei said that enhanced mobile broadband needs higher bandwidth and higher data transmission rate, so it is more likely to use millimeter wave. He pointed out that 5g can also operate in the frequency band below 6GHz, and it is entirely possible for the traditional 2G / 3G spectrum to be used for 5g“ The reason why millimeter wave was not used in 2G / 3G before is that the transmission performance of millimeter wave is worse than that in low frequency band. When transmitting data in open space, the absorption of oxygen molecules is more obvious than the low-frequency spectrum, so the millimeter wave spectrum decays faster. In addition, the ability of this spectrum to pass through / around obstacles is poor. In order to get a higher data transmission rate, we must have a higher bandwidth. In order to get a higher bandwidth, we choose to use millimeter wave. Therefore, the answer to how to offset the disadvantage of millimeter wave is precisely on the higher frequency of millimeter wave. " Shen Lei said that its disadvantages can be well compensated or even offset by using adaptive beamforming and beam tracking technology. In fact, millimeter wave length means smaller antennas, but more antennas need to be integrated to work together“ The advantage of multiple antennas is that it can form an antenna array, and each antenna will emit its own amplitude and phase. If we can control these antennas wisely and make the space of each electromagnetic wave emitted by them offset or enhance each other, we can form a beam instead of omnidirectional transmission. "
According to the results of the research and development test of 5g millimeter wave, UE can intelligently select the best sub antenna array for receiving and transmitting; The selected sub antenna array uses beam tracking and beam control to track the associated beam from eNodeB (ENB); Even in the scenario of non line of sight RF channel and UE movement, stable mobile broadband communication can be realized“ Through experiments, we found that through beamforming technology, reflection and refraction, millimeter waves can still pass through obstacles and have a good non line of sight transmission effect. Therefore, the confidence of the whole industry has been significantly enhanced. "
Xiaolong X50 5g platform includes modem, sdr051 millimeter wave transceiver and supporting pmx50 power management chip. Xiaolong X50 5g modem is expected to start sampling in the second half of 2017, and the first batch of commercial terminals is expected to be launched in the first half of 2018“ This will basically cooperate with the test and deployment of Verizon 5g TF and Korea Telecom, and they will decide the specific time period. " Shen Lei said, "our goal is to accelerate the formulation of 5g global standard - 5g new radio (NR, new radio)."
4G LTE and 5g will coexist for a long time
"5g is not produced out of thin air. It is the accumulation of 4G LTE and other communication technologies. It has developed very smoothly to 5g." Shen Lei said that Gigabit LTE is a very important step in the development of 5g, and many of its technologies are paving the way for 5g. There are many possibilities for 5g to use spectrum, millimeter wave and multi antenna array
Our other product:
