I. Project Background of Backpack Mobile Communication and Reinforced Communication Equipment
Shortwave communication equipment (frequency range 3-30 MHZ), as a traditional but irreplaceable wireless communication technology, its application background is mainly based on its unique technical advantages and rigid demands in specific scenarios. Analysis of the core application background of shortwave communication:

Irreplaceable communication guarantee requirements
▲ Invulnerability and autonomous communication capability
Shortwave communication does not rely on network hubs or relay facilities such as satellites and base stations. The equipment deployment is flexible. In extreme environments such as war and disasters, when satellites are destroyed or ground infrastructure is paralyzed, shortwave becomes the only reliable communication means. For instance, during the Wenchuan earthquake, shortwave radio stations and satellite phones were used in combination, solving the problems of insufficient satellite resources and terrain obstacles. In the military field, it is even regarded as a guaranteed communication method for battlefield command, and it can still operate especially in an environment with severe electromagnetic interference.
▲ Global coverage capability
Shortwave can achieve beyond-line-of-sight communication over thousands of kilometers through ionospheric reflection (sky wave propagation), with a coverage far exceeding that of ultrashort wave and microwave, and even satellite communication is difficult to completely replace it. For instance, in areas such as the Gobi and the ocean where there is no ground network coverage, shortwave is the only economically feasible option for long-distance communication.

Economy and wide applicability
1.Low-cost advantage
   Shortwave equipment has a low cost and does not require satellite call charges or base station maintenance fees, making it suitable for scenarios with limited budgets. For instance, in civilian fields such as agriculture and fishery, shortwave is used to achieve low-cost early warning information release and daily communication.
2. Multi-field universality
▲ Military and national defense: It is used for battlefield command, tactical communication and electronic countermeasures. For instance, Australia's HF-90H frequency-hopping radio enhances its anti-interference capability through intelligent frequency modulation.
▲ Emergency disaster relief: Quickly establish emergency communication networks in disasters such as earthquakes and floods to ensure rescue command.
▲ Navigation and aviation: The Global Maritime Distress and Safety System (GMDSS) relies on shortwave for ship-shore communication, and high-altitude aircraft also require shortwave as a backup communication means.
▲ Communication in remote areas: In regions lacking infrastructure such as mountainous areas and polar regions, shortwave becomes the only communication option.
3. Demand for high-speed data transmission
   Traditional shortwave mainly consists of voice and low-speed data. However, in recent years, through technologies such as OFDM multi-carrier modulation and PACTOR-Ⅲ protocol, it has supported image transmission and integrated service networking, meeting new demands such as fishery early warning and logistics monitoring.

Driven by policy and security demands
1.National security and confidentiality
Shortwave communication inherently possesses anti-interception characteristics. Combined with encryption and frequency-hopping technologies, it has become an important tool in military and sensitive fields. For instance, in the process of domesticating military communication equipment in China, shortwave technology has always occupied a core position.

2. International standards and industry norms
The International Telecommunication Union (ITU) continuously optimizes the allocation of shortwave spectrum, promotes the application of standardized protocols (such as AX.25 and CCIR493), and enhances the compatibility and scalability of global shortwave networks.

Future challenges and development directions
Although shortwave communication is irreplaceable in terms of invulterability and coverage capability, it still faces technical bottlenecks such as narrow frequency band and multipath interference. The future development directions include:
Adaptive frequency hopping and modulation technology: Real-time response to ionospheric changes to enhance channel utilization.
▲ High-frequency band expansion and 5G integration: Explore the combination of high-frequency boards and 5G technology to support low-latency, high-bandwidth tactical communication networks.
▲ Ecological collaborative application: Combined with emerging technologies such as the Internet of Things and unmanned aerial vehicles, it expands scenarios such as environmental monitoring and intelligent transportation.
   In conclusion, the application background of shortwave communication equipment is rooted in its irreplaceable reliability, economy and wide applicability. Especially in military, emergency, remote areas and special industry scenarios, it remains an indispensable communication means. With the iteration of technology and the upgrading of demands, shortwave is transforming from "guaranteed communication" to "intelligent integrated service platform", and will play a key role in more fields in the future.
   With the rapid development of portable communication devices, new standards and requirements for power supply guarantee are constantly being put forward. Lithium batteries, with their advantages of high energy density, portability, long cycle life and environmental friendliness, have almost completely replaced traditional batteries and become the preferred solution for portable communication systems. This solution is designed for the lithium battery application requirements of backup mobile communication and reinforced communication equipment projects, meeting the high demands of diversified applications. Lithium batteries provide safe, efficient and customized power solutions under various complex environmental conditions of the equipment.

II. Analysis of Equipment Demand Characteristics
1. Equipment application characteristics
▲ Equipment types: Emergency communication, emergency rescue, unmanned operation, etc. in extreme environments, wireless transmission, etc.
▲ Working environment: Temperature range, -40℃ to +70℃.
▲ Power demand: Large continuous/peak power, long battery life. The voltage platforms generally adopt 3.7V, 7.4V, 12V, 24V, 36V, etc.

2. Core requirements for lithium batteries
▲ High safety: Meets the requirements of explosion-proof, shock resistance, and resistance to high and low temperatures under the harsh working conditions of special equipment.
▲ Long cycle life: ≥500 times (80% capacity retention rate).
▲ Fast charging: Supports 2 to 3 hours of fast charging, suitable for high-intensity work.
▲ High-power discharge: The battery supports continuous high-current discharge, meeting the high-current requirements of high-power devices and ensuring their continuous and stable operation.
▲ Intelligent management: The BMS (Battery Management System) is equipped with functions such as overcharge protection, overdischarge protection, overcurrent protection, short-circuit protection, temperature protection, and fault diagnosis, making the battery more intelligent.
Discharge temperature range: -40℃ to +70℃. In a low-temperature environment of -40℃, the battery's discharge efficiency is over 70%. A wider range of ambient temperature adaptability.
Charging temperature: -20℃ to +50℃ range, with a wider adaptability to environmental temperatures.

III. Scheme Design
1. Battery selection
▲ Cell types: Ternary lithium batteries (ultra-low temperature, high energy density, high safety), lithium iron phosphate batteries (ultra-low temperature, high safety, long life), sodium-ion batteries (high safety, long life, good low-temperature performance). Different system cells are selected and matched according to different application scenarios.
▲ Battery combination configuration structure: Series and parallel schemes are designed based on the required voltage and capacity of the equipment to meet the requirements of different output voltage platforms.
▲ Structural design: IP65-IP68 protection grade, shock-resistant structure, explosion-proof, corrosion-resistant enclosure (suitable for extreme or high-pressure environments).

2. BMS Management System
Core functions:
Real-time monitoring of the voltage, temperature, SOC (State of Charge), and SOH (State of Health) of individual battery cells.
The battery charging active balancing technology enhances the consistency of usage among battery cells and extends the lifespan of the battery pack.
The I2C/SMBUS/CAN/RS485 communication interface enables data interaction and communication with the main control system of the equipment.
The Coulomb computing method makes the battery SOC more accurate and the battery smarter.

3. Charging solution
▲ Charging equipment: Customized smart charger/charger/charging cabinet, supporting constant current and constant voltage (CC-CV) charging.
▲ Charging strategy: Select fast charging or slow charging mode based on the working conditions to prevent battery overload.
▲ Intelligent control and management: Based on the technical performance characteristics of the battery, the battery charging process and fault diagnosis are intelligently controlled.

IV. Safety and Compliance
1. Safety protection
▲ Thermal management: By adopting a reasonable structural layout, thermal runaway is reduced, and physical temperature control is possible (for high-power scenarios), ensuring temperature uniformity during battery use and effectively controlling battery thermal runaway.
▲ Fault protection: Multiple hardware protection mechanisms such as overcharge, overdischarge, short circuit, overcurrent, and over-temperature.
▲ Fault protection: Multiple hardware protection mechanisms such as short circuit, overcurrent, and over-temperature.
▲ Explosion-proof certification: The design can pass various safety regulations certifications.

5. Standard compliance
It complies with national standards such as GB31241-2022 (Safety Technical Specification for Lithium-ion Batteries and Battery Packs for Portable Electronic Products), GB 17761-2024 (Safety Technical Specification for Electric Bicycles), GB/T 34131 (Lithium Batteries for Power Storage), GB 38031 (Safety Requirements for Batteries for Electric Vehicles), etc.
How to obtain domestic and international certifications: GB certification, UN38.3 certification, UL certification, IEC certification, CE certification and other various certification requirements.

V. Project Implementation Plan

VI. Economic Benefit Analysis
1. Cost direction
As a new type of energy product, lithium batteries are energy-saving and environmentally friendly, portable and lightweight, with low costs and easy maintenance. Compared with AC wired power supply, they are superior.
2. Energy-saving benefits:
The charging efficiency is over 95%, significantly reducing energy consumption.
3. Maintenance cost:
The maintenance-free design significantly reduces manual inspection and manufacturing costs.

VII. After-sales Service
1. Warranty period: 1 to 5 years of after-sales warranty, with a lifespan of over 500 to 800 cycles (whichever comes first).
2. Remote monitoring: According to the actual demand status, the cloud platform provides real-time monitoring of the battery status and early warning of potential faults.
3. Emergency Response: Respond within 4 hours, provide solutions within 8 hours, and offer on-site technical support within 24 to 48 hours.

Hint:
   The plan needs to be refined based on specific equipment parameters (such as voltage, capacity, and size limitations).
   If special environments (such as explosion-proof and high pressure) are involved, corresponding protective designs need to be added.
   It is recommended to conduct joint debugging with the equipment manufacturer to ensure the compatibility of the battery with the entire machine system.