eMTC, as one of the mainstream standards for narrowband cellular IoT networks, possesses the four basic capabilities of LPWA compared to non-cellular IoT: wide coverage, massive connectivity, low power consumption, and low cost.
First, low power consumption and long terminal battery life. Currently, 2G terminals have a standby time of only about 20 days. In some typical LPWA applications, such as metering services, 2G modules clearly cannot meet the requirements of special locations like deep wells and chimneys where batteries cannot be replaced. eMTC consumes only 1% of the power of a 2G modem, with a standby time of up to 10 years.
Second, massive connectivity to meet the demand for “massive connections.” One major characteristic of IoT terminals is the ability to connect massive users. Networks designed for non-IoT applications cannot meet the need for simultaneous access by a large number of terminals, while eMTC supports over 10,000 terminals per cell.
Third, insufficient network coverage in typical scenarios. For example, coverage blind spots like deep wells and underground garages cannot be fully covered by outdoor 4G base stations. In terms of wide coverage, eMTC is 15dB better than LTE (can penetrate one more wall) and 11dB better than GPRS, with signals covering up to 2-3 underground floors.
Fourth, costs are expected to continue to decrease. Currently, the mainstream communication technology for smart home applications is Wi-Fi. Although Wi-Fi modules are relatively inexpensive, having dropped below 10 yuan, IoT devices supporting Wi-Fi typically require a wireless router or wireless AP for network access or can only communicate within a local area network. 2G communication modules generally cost over 20 yuan, while 4G communication modules exceed 150 yuan. In contrast, eMTC terminals are expected to continuously lower costs through cross-subsidization within the industrial chain.
Fifth, dedicated frequency bands have less interference. Compared to non-cellular IoT technologies, eMTC transmits based on authorized spectrum, resulting in less interference, better security, and higher reliability.
For a long time, the two cellular IoT standards, eMTC and NB-IoT, have had a competitive relationship, and there has been ongoing debate about which network standard to choose. In fact, both have their technical advantages and a basis for cooperation, and there is no best choice. The competition mainly revolves around module chip costs, commercialization levels, and the completeness of network construction.
The industry debate officially ended in June 2017. At the 76th 3GPP plenary meeting, the industry reached a consensus on the evolution direction of mobile IoT technologies (including NB-IoT and eMTC) R15: no new eMTC terminal types with system bandwidth below 1.4MHz will be added; no new NB-IoT terminal types with system bandwidth above 200KHz will be added.
This decision from 3GPP has promoted the orderly development of M-IoT, allowing eMTC and NB-IoT to clearly delineate application boundaries and transition to a hybrid networking and differentiated complementary cooperative relationship.
The Technical Relationship Between the Two
In terms of peak rate, NB-IoT supports a data rate of only 200kbit/s, while eMTC can reach 1Mbit/s; regarding mobility, NB-IoT lacks automatic cell switching and thus has almost no mobility, while eMTC performs better in mobility; in terms of voice, NB-IoT does not support voice transmission, while eMTC does; concerning terminal costs, NB-IoT has standardized modules and chip types, which have now dropped to around 5 dollars, but eMTC’s current price remains relatively high and decreases slowly; regarding cell capacity, eMTC has not undergone directional optimization and struggles to meet the demand for ultra-large capacity connections; in terms of coverage, NB-IoT has a coverage radius that is 30% larger than eMTC, with eMTC being about 9dB worse than NB-IoT.
|
Comparison Item |
NB-IoT |
eMTC |
|
Frequency Band |
FDD |
FDD, TDD |
|
Deployment |
LTE in-band, LTE guard band, standalone |
LTE in-band |
|
Duplex |
HD |
HD/FD |
|
Number of Antennas |
1/2 (RxD) |
1/2 (RxD) |
|
Carrier Bandwidth |
200kHz |
1.4MHz |
|
Uplink Coverage |
Gain: 20+dB |
Gain: 15+dB |
|
Downlink Coverage (MCL) |
164dB |
156dB |
|
Peak Rate |
UL: 250kbit/s (MT)/200kbit/s (ST) DL: 250kbit/s |
UL: 1Mbit/s (FD)/375kbit/s (HD) DL: 1Mbit/s (FD)/300kbit/s (HD) |
|
Subcarrier Bandwidth |
UL: single tone: 15/3.75kHz multi tone: 15kHz DL: 15kHz |
UL: 15kHz DL: 15kHz |
|
TTI |
1ms |
1ms/8ms |
|
Modulation |
BPSK QPSK |
QPSK 16QAM |
|
Multiple Access |
UL/DL: SC-FDMA/OFDMA |
UL/DL: SC-FDMA/OFDMA |
|
Mobility |
Low speed, cell reselection |
Low to medium speed, cell handover |
|
Latency |
Seconds level |
100ms level |
|
Voice |
Not supported |
Supported |
|
Cell Capacity |
Target capacity 50k/cell |
Target capacity 50k/cell |
|
Positioning |
Future support (R14, E-CID/UTDOA/OTDOA, target <50m) |
Standard already supports (about 50m) |
|
Power Consumption |
PSM, eDRX |
PSM, eDRX |
|
Chip Cost |
Target <1 dollar (lower than eMTC) |
Target 1~2 dollars |
|
Module Cost |
Target 2~5 dollars |
Slightly higher than NB-IoT |
|
Standard Introduction Version |
R13, 2016 |
R13, 2016 |
Table: Comparison of NB-IoT and eMTC (Source: WeChat Official Account LPWAN Technology)
Hybrid Networking of Both in Application Scenarios
From the technical characteristics of both, NB-IoT excels in coverage, power consumption, cost, and connection numbers, typically used in static scenarios that pursue lower costs, broader coverage, and longer battery life; eMTC currently lags behind NB-IoT in coverage and module costs, but has advantages in peak rates, mobility, and voice capabilities, making it more suitable for scenarios requiring voice calls, high bandwidth rates, and mobility. In real market usage scenarios, both can form a complementary relationship.
Forecast data shows that the connection ratio of NB-IoT to eMTC is 8:2 due to its low cost and wide coverage. However, eMTC network application scenarios are more diverse, and the relationship between applications and users is more direct, resulting in higher ARPU values for users in eMTC network environments.
In the “Mobile IoT Industry Solution White Paper” published by China Mobile, it can be seen that the hybrid networking of NB-IoT/eMTC will lead to richer application scenarios. NB-IoT technology applications involve static scenarios, such as smart metering, smart switches, and smart manhole covers. However, after the hybrid networking of NB-IoT/eMTC, it will involve more interactive and collaborative IoT applications, such as full-process product management, smart parking, shared bicycles, financing leasing, container monitoring, smart greenhouses, animal traceability, forestry data collection, remote health, smart streetlights, air monitoring, and smart homes.
Therefore, the simultaneous promotion of NB-IoT and eMTC can meet the comprehensive needs of multiple scenarios.
Based on the different application scenarios of NB-IoT and eMTC, international operators have shown clear differences in their cellular IoT deployment strategies from a business development perspective.
According to the latest report on the evolution of cellular IoT released by GSMA, Verizon, AT&T, and Telstra have deployed eMTC commercial networks, while Vodafone (Spain, Netherlands), Deutsche Telekom, KT (Korea), and China Telecom have deployed NB-IoT commercial networks. Meanwhile, Etisalat in the UAE has deployed both NB-IoT and eMTC commercial networks.
Prioritize eMTC Deployment
Leading international operators such as AT&T and Verizon have first completed eMTC deployment. As early as 2016, AT&T and Verizon began the race for network deployment. In August of that year, Verizon announced plans to achieve the first eMTC commercial network in North America and announced the completion of its eMTC commercial network deployment in the U.S. in March 2017. In October 2016, AT&T launched the first eMTC commercial base station in San Francisco, and now AT&T has completed eMTC commercial deployment in the U.S. and plans to complete eMTC network deployment in Mexico by the end of the year. Telstra followed the lead of U.S. operators, completing nationwide eMTC commercial deployment in August this year.
The eMTC networks of AT&T, Verizon, and Telstra are currently the three largest in the world, all supported by Ericsson for deployment.
Clearly Support NB-IoT Development
European and Asian operators are the main promoters of NB-IoT technology, especially Vodafone, Deutsche Telekom, and KT. Vodafone’s global deployment progress continues to accelerate. In early 2017, Vodafone launched the first NB-IoT commercial network in Spain and completed its NB-IoT trial on a commercial network for the first time. In August 2017, Vodafone launched the NB-IoT network in nine cities in the Netherlands, and in September, the first nationwide NB-IoT network in Ireland; actively conducting tests and accelerating the launch of commercial networks in New Zealand, Australia, and other places.
In early 2017, Deutsche Telekom announced plans to deploy a pan-European NB-IoT commercial network, starting in Germany and then gradually commercializing in the Netherlands, Austria, Croatia, Greece, Hungary, Poland, and Slovakia.
In November 2016, KT and LG U+ jointly announced their NB-IoT strategy, aiming to complete nationwide coverage of the NB-IoT network by 2017. By mid-year, LG U+’s NB-IoT network construction had been basically completed.
Continuously Follow eMTC and NB-IoT
The technical competition and the complementary business scenarios have led some international operators to promote the joint deployment of eMTC and NB-IoT. After completing eMTC deployment, Telstra announced that it would also complete the nationwide deployment of NB-IoT within this year. In July 2017, Etisalat announced the launch of eMTC and NB-IoT commercial networks, becoming the first operator in North Africa to provide these new technologies, thus supporting the realization of various solutions and services.
The Chinese government places great importance on the development of IoT and has introduced multiple supportive measures at the policy level, establishing future development goals. Domestic basic operators are actively promoting IoT development, accelerating the construction of NB-IoT networks while also actively following up on eMTC.
The National Policy Highly Supports IoT Development
In the “Guiding Opinions of the State Council on Promoting the Orderly and Healthy Development of the Internet of Things,” “Made in China 2025,” and “Guiding Opinions of the State Council on Actively Promoting the ‘Internet Plus’ Action,” various requirements for IoT development have been proposed. The Ministry of Industry and Information Technology (MIIT) released the “Information and Communication Industry Development Plan for IoT (2016-2020)” which states that by 2020, an IoT industry system with international competitiveness should be basically formed, with the overall industry scale exceeding 1.5 trillion yuan and the number of public network M2M connections exceeding 1.7 billion.
In June 2017, the MIIT issued a notice on “Comprehensively Promoting the Construction and Development of Mobile IoT (NB-IoT),” pointing out that network deployment should be accelerated to build the NB-IoT network infrastructure. Basic telecom enterprises should increase the deployment of NB-IoT networks, provide good network coverage and service quality, and comprehensively enhance the access support capabilities of NB-IoT. By the end of 2017, achieve NB-IoT network coverage in municipalities and provincial capital cities, with the scale of base stations reaching 400,000.
By 2020, NB-IoT networks should achieve nationwide coverage, realizing deep coverage for applications such as indoor, transportation networks, and underground pipelines, with the scale of base stations reaching 1.5 million. Strengthen the construction of IoT platform capabilities, support massive terminal access, and enhance big data operation capabilities.
Domestic Basic Operators Accelerate the IoT Construction Process
Based on the 800MHz low-frequency coverage advantage, China Telecom leads in NB-IoT construction. In the first half of 2017, China Telecom announced the commercial use of NB-IoT networks and has established strategic cooperation with Shenzhen Water Group, ofo, Hisense, Haier, and others. China Telecom is not only developing NB-IoT but also paying attention to eMTC technology. At the “9th Tianyi Smart Eco-Industry Summit Forum” held on July 27, the chairman of China Telecom, Yang Jie, stated that in the second half of 2017, they would conduct eMTC validation tests and plan to achieve commercial deployment in 2018.
China Unicom, while promoting the pilot commercial use of NB-IoT, has initiated an eMTC pilot and believes that these two technologies have a complementary relationship.In 2016, China Unicom had already initiated large-scale networking trials based on NB-IoT in seven cities (Beijing, Shanghai, Guangzhou, Shenzhen, Fuzhou, Changsha, Yinchuan) using 900MHz and 1800MHz, as well as more than six business application demonstrations. In 2018, they plan to fully promote the nationwide commercial deployment of NB-IoT. China Unicom has opened an eMTC trial network in cities like Beijing and completed the end-to-end business process by the end of 2016, currently promoting IoT applications based on eMTC.
On June 29, 2017, at the Mobile IoT Conference held by China Mobile, Deputy General Manager Sha Yuejia elaborated on the development strategy of China Mobile’s IoT, committed to simultaneously promoting the collaborative development of NB-IoT and eMTC to achieve technical complementarity and industrial progress. They plan to conduct large-scale trials of NB-IoT and eMTC in Hangzhou, Shanghai, Guangzhou, and Fuzhou, with subsequent commercial deployment in multiple key cities, aiming for nationwide commercial use in 2018.
In summary, NB-IoT and eMTC do not have opposing relationships; rather, due to different application scenarios, operators will choose to collaborate on both to expand the industrial chain, continuously drive consumption upgrades, provide manufacturers with more application scenarios unrestricted by technology, enhance user experience, stimulate users’ rigid demand, and lay the foundation for the integration of 5G with various industries. This is the future trend of the integrated development of NB-IoT and eMTC.
Author: China Academy of Information and Communications Technology, Yu Quan; Shanxi Mobile Wang Feng
Source: “Communication World” Issue 29, Total Issue 753
