Introduction: When urban density encounters communication limits ‌
Shanghai Nanjing Road Pedestrian Street, 20 mobile phones are connected simultaneously per square meter; Shenzhen Huaqiangbei Electronics Market, an average of 100,000 devices compete for network resources every day; Beijing Guomao Subway Station, more than 50,000 data requests per second during peak hours in the morning and evening... With the outbreak of smart city applications, traditional 5G base stations are frequently "overloaded" in areas with excessive density of people and equipment, and user experience has plummeted.
This deadlock is being broken by the combination of millimeter wave technology and smart antennas. In June 2024, China Unicom and Huawei completed the deployment of the world's first 5G-A (5G-Advanced) millimeter wave smart base station group in Tianhe District, Guangzhou. Actual measurements show that in the scenario of millions of devices accessing per square kilometer, the network delay is stable within 1 millisecond, and the peak rate of a single user exceeds 10Gbps. This technological revolution driven by "high frequency band + high intelligence" is redefining the connection paradigm of smart cities.

‌1. Technical breakthrough: the chemical reaction of millimeter wave and smart antenna‌
Millimeter wave (24.25-52.6GHz) is regarded as the ultimate weapon to solve the capacity crisis due to its ultra-large bandwidth (starting from 800MHz), but its physical characteristics have deterred the industry: short coverage radius, high penetration loss, and beam susceptibility to interference. The three core technological breakthroughs of smart antennas have truly unleashed the potential of millimeter waves:

‌1. Three-dimensional dynamic beamforming‌
Huawei AirEngine 8781 smart antenna is equipped with 1024 array elements. It uses AI algorithms to track user locations in real time and form a 0.5° narrow beam to accurately "lock" the terminal. In the Guangzhou Tower test, the dynamic beam extended the coverage distance of millimeter waves from 200 meters to 800 meters, and reduced signal fluctuations by 90%.

‌2. Intelligent Reflective Surface (RIS) blind spots‌
The "Spiritual Realm" intelligent reflective panel developed by ZTE can be deployed on the exterior walls of buildings or street lamp poles to diffract millimeter wave signals to blind spots. Data from the Shanghai Lujiazui pilot project showed that RIS reduced the penetration loss of glass curtain walls from 40dB to 12dB, and increased the indoor download rate by 8 times.

‌3. Multi-band collaborative scheduling‌
Ericsson's spectrum sharing solution allows millimeter wave and Sub-6GHz bands to "divide and cooperate": low-frequency bands are responsible for wide-area coverage, and high-frequency bands specialize in hot spots. After applying this technology in the Chunxi Road business district in Chengdu, network capacity increased by 12 times and operation and maintenance costs decreased by 35%.

‌II. Scenario Revolution: "Connection Scalpel" for High-density Cities‌
Millimeter wave intelligent base station clusters demonstrate disruptive value in three typical scenarios:

‌Scenario 1: Hub with more than 10,000 people‌
Beijing Daxing Airport deploys millimeter wave intelligent antenna system:
The rate of each terminal in the check-in area is ≥1Gbps, and passengers can download 4K movies in 30 seconds.
The baggage sorting robot transmits real-time video through the 28GHz frequency band, and the sorting accuracy rate is increased from 99.5% to 99.99%.
The emergency command center uses the low latency characteristics of millimeter waves to achieve synchronous AI analysis of 400 cameras, and the emergency response speed is increased by 5 times.
‌Scenario 2: Industrial Internet of Things Concentrated Areas‌ ‌Sany Heavy Industry Changsha Smart Factory‌ has built the world's first millimeter wave 5G private network:
5,000 sensors are directly connected through smart antennas, and the equipment status collection cycle is compressed from minutes to milliseconds.
The navigation positioning accuracy of the AGV car is ±2mm, and the production line change efficiency is increased by 40%.
Huawei's calculations show that the millimeter wave delay stability is 100 times higher than Wi-Fi 6, and can support 0.01ms-level synchronous control.
‌Scenario 3: 8K ultra-high-definition video ecology‌ ‌Hangzhou Asian Games Village‌ millimeter wave base station supports multi-view 8K live broadcast:
The audience can freely switch 16 camera positions in the VR helmet with a delay of <10ms.
120 8K cameras outside the venue transmit images in real time, AI automatically generates game highlights, and content production efficiency is increased by 50 times.
China Mobile data shows that a single base station can carry 200 8K video streams at the same time, with a traffic density of 3000Tbps/km².
‌III. Industry Chain Resonance: Ecological Reconstruction from Equipment Vendors to Operators‌
The large-scale deployment of millimeter wave smart antennas is reshaping the communications industry landscape:

‌1. Equipment Vendors: From Hardware Manufacturers to Solution Integrators‌
Huawei launches the "mmWave-as-a-Service" model, where customers can purchase network capabilities based on traffic density.
Nokia develops the world's first foldable millimeter wave base station, which is 60% smaller and supports temporary deployment of drones.
‌2. Operators: Redefine Network Value‌
China Telecom launches a "density billing" package, where shopping malls and venues pay according to the peak number of connections, which is 70% lower than traditional private networks.
Deutsche Telekom sells millimeter wave slicing capabilities to car companies, with each self-driving car paying an average of 45 euros per year for connection fees.
‌3. Policy dividends: China leads the standard setting‌
The Ministry of Industry and Information Technology's "5G Millimeter Wave Smart Antenna Technical Specifications" requires that new base stations support AI beam optimization from 2025. Shenzhen City provides a 30% electricity fee subsidy for business districts that deploy millimeter wave base stations, which is expected to drive smart business investment of more than 20 billion yuan.

‌IV. Challenges and the future: from connection density to urban intelligence‌
Despite rapid progress, millimeter wave smart antennas still need to overcome three major difficulties:

‌Coverage cost‌: The coverage area of ​​a single base station is only 1/10 of that of Sub-6GHz. ZTE has developed "smart street light base stations" to reduce deployment costs by 60%.
‌Terminal ecology‌: The global millimeter wave mobile phone penetration rate is less than 15%. OPPO and vivo plan to achieve full-series model support in 2025.
‌Energy consumption control‌: The power consumption of millimeter wave base stations is 3 times higher than that of traditional base stations. Ericsson's liquid cooling solution can reduce energy consumption by 40%.
The future technology evolution path is clearly visible:

‌AI-RAN Convergence‌: Qualcomm is developing a built-in AI chip in the base station that can predict the user's movement trajectory and pre-allocate beam resources.
‌Terahertz Evolution‌: Southeast University Laboratory has achieved 6G prototype verification in the 100GHz frequency band, with a rate exceeding 1Tbps.
‌Digital Twin Operation and Maintenance‌: China Unicom has built a "city signal heat map" that can simulate network performance in extreme scenarios such as heavy rain and large-scale events.
‌Conclusion: Make every inch of urban space "signal free"‌
When millimeter wave smart antennas weave "invisible optical cables" between skyscrapers, and when massive data flows in an orderly manner in the 1mm wavelength electromagnetic wave, 5G-A technology is pushing smart cities into a new era of "connection freedom". This is not only an upgrade of communication capabilities, but also a paradigm shift in urban governance from "people adapting to the network" to "network adapting to people". In this millimeter wave revolution led by China, every base station is writing a footnote for the future of the city-there are no signal dead spots, only infinite possibilities.