Security Protection Wireless Internet Of Things System With OFDM Adaptive Adjustment

Adaptive Cognition and Security Protection for Wireless/Internet of Things Operation Temperature 

The wireless Internet of Things system is essentially a software defined radio technology implementation. Considering the requirements for long-distance/anti-interference communication capabilities, the physical layer adopts OFDM adaptive adjustment method and optimizes channel estimation, which can effectively compensate for Doppler frequency offset, support vehicle movement at 80 kilometers per hour, and achieve cross base station switching or dynamic self-organizing network in self-organizing network mode. The MAC layer adopts 802.11 connectionless mode and corresponding frame format, optimized and enhanced for mobility. To avoid bandwidth loss caused by multi node CSMA/CD conflict detection, the system implements uplink time-division multiplexing, which can effectively support applications with multiple video uploads.

Network function

Broadband RF front-end

Support multiple channel bandwidths

Support frequency scanning function

Support fixed and rate adaptive

Support power control

Support community reselection/switching

Support QoS

Support multiple networking methods

 

The independently innovated OFDM/CDMA air interface of the adaptive cognitive wireless Internet of Things system effectively combines the efficient transmission capability of OFDM with the long-distance anti-interference communication capability of CDMA, and has completed product implementation in the UHF frequency band. The system has a large working bandwidth, can reliably perceive the spectrum environment, and has the ability to dynamically select the spectrum. It can self adjust the transmission and reception parameters (channel bandwidth, transmission power, modulation method, dynamic adaptive coding, etc.), and can autonomously optimize the communication effect.

The system does not require a core network, and the network topology can be flexibly configured according to needs. It can adopt master-slave, ad hoc, and relay networking modes, and the network deployment is simple.

The adaptive cognitive wireless system can be extended from the UHF band (470-698MHz) to the L-band 1.4GHz for implementation. The system uses idle digital TV channels and utilizes the excellent propagation characteristics of the UHF frequency band to optimize the combination of bottom noise, bandwidth, transmission power, antenna and other parameters. The system can achieve long-distance transmission of wireless signals. Transmission distance for typical scenarios:







 

Being able to dynamically select spectrum based on supply and demand, and flexibly configure channel bandwidth;

Supports frequency hopping and has strong resistance to interference;

Support cross base station handover and report good mobility;

Support point to multipoint, self-organizing network, and fast convergence of self-organizing network topology;

Low loop latency<5ms, supporting control class low latency requirements;

Symmetric uplink and downlink, adaptive allocation of uplink and downlink bandwidth, all bandwidth can be allocated to the uplink;

Facing connectionless environments, with strong anti-interference capabilities;

The wireless transmission system based on IP has a wide range of applications and can carry various services such as video, voice, and data;

Time division uplink multiplexing effectively supports video uplink transmission;

Good transmission capability, supporting non line of sight transmission, superior to the transmission distance and penetration capability of 3G/4G/5G;

Flat network structure, flexible deployment, no need for a dedicated core network;

The system is easy to use and maintain;

Support external encryption machines based on IP addresses for commercial and national encryption;

 

 

Point to point method, using directional antennas, with a hanging height generally above 30 meters, mainly used to solve the non line of sight and high bandwidth transmission needs between points.
 

For multi-point mode, both the base station and the user end use directional antennas, with the base station hanging at a height of generally 30 meters or more and the user end hanging at a height of 5 meters or more, to meet the requirements of non line of sight, point to multipoint, and access.



The networking method is an enhancement of the point-to-point approach. If continuous channels are insufficient to support the bandwidth required for point-to-point mode, non continuous channel bundling can be used to increase the provided bandwidth.



In scenarios where spectrum resources are insufficient, by highly isolating different sectors (3 meters), it is possible to support three sector same frequency networking and multi terminal access.



In scenarios with sufficient spectrum resources, three sectors can use inter frequency networking and support multi terminal access.
 

The adaptive cognitive wireless system equipment consists of a baseband, transceiver, amplifier, and antenna combination. By combining different baseband, transceivers, amplifiers, and antennas, the system can be constructed in various forms such as handheld, airborne, backpack, vehicle mounted, shipborne, and vehicle mounted.

 UHF 2x4W

UHF handheld