Application of wireless mesh network technology in intelligent community security

Smart residential security is the current development trend. Since residential surveillance systems are very cost-sensitive, the use of wireless technology can save more than 90% of the cost compared to wired solutions. This article will discuss the solution and analysis of using wireless Mesh technology to build smart residential security.

Compared with traditional analog video surveillance networks, today's IP network video surveillance systems provide a powerful solution that provides greater flexibility, reliability and further reduces deployment costs. In the past, wireless video surveillance was considered a point-to-point solution with poor reliability. As more and more users implement video surveillance on Strix wireless mesh networks, wireless mesh networks have changed this perception. Coverage distances and ranges that were considered impossible in the past few years have been achieved through the robust high performance, low latency and multi-hop scalability of wireless mesh networks.

From a global perspective, the video surveillance market can reach more than 10 billion US dollars. According to a report by iSuppli Corporation, video surveillance equipment will reach 12 billion US dollars by 2011, including video surveillance cameras, DVRs and video servers. "It is expected that in 2015-2016, network-based monitoring systems will completely replace analog monitoring systems," IMS Research pointed out that by the end of 2009, "analog recording equipment will only account for 5% of the market share."

With the expansion of existing network deployment and the development of new network digital monitoring systems, the development of the IP video surveillance market is also a natural progression. With the transition from DVR digital video recording to NVR (network video recording) technology, the development of IP technology applications in the video surveillance market is also rapidly popularizing. In addition, IP video surveillance technology will also expand the video surveillance market, covering more new applications and new market segments. Wireless Mesh network technology has also become a new direction for the video surveillance market.

Strix Wireless Mesh Network facilitates large-scale distributed video surveillance deployment, providing the industry's highest throughput, lowest latency, unparalleled flexibility and reliability for IP video surveillance systems. Strix Wireless Mesh Network is widely deployed around the world, especially when users require wireless network performance to be comparable to wired networks or to provide bearer for critical surveillance systems. Strix Access/One? is the industry's only wireless network architecture that has been independently tested and verified by actual global deployment.

Traditional deployment uses coaxial cables, expensive fiber optic multiplexers, distributed amplifiers, and even private twisted-pair solutions similar to Ethernet cables. Now the situation is changing rapidly. By eliminating the limitations of cables, many deployment barriers and additional costs are reduced, and monitoring systems that were previously impossible to implement have become possible. As long as they are within the coverage of the wireless Mesh network architecture, video surveillance heads and video servers can be placed arbitrarily. Therefore, more users have discovered the advantages of this solution and it is gradually replacing traditional analog video surveillance systems.

Distributed video surveillance network helps build intelligent community security system

Strix wireless mesh network enables large-scale deployment and strategic IP video surveillance. Video surveillance is a key application system, especially for government, municipal, public safety or enterprise security. It is also very suitable for price-sensitive residential intelligent systems.

Distributed video surveillance provides powerful viewing, sharing and distribution capabilities, and cooperates with statistical information and integrated information of access control systems or intrusion monitoring systems to eliminate the hidden dangers of centralized server clusters and single points of failure. Strix provides a fully distributed wireless Mesh video surveillance system, including video cameras, video servers, storage clusters, customer application systems and remote viewing.

In addition, network video surveillance, in conjunction with applications such as remote alarm systems, further improves the efficiency of the security department and reduces the response costs of false alarms. According to statistics, for most government and enterprise units, this function reduces the false alarm rate by 90%.

Advantages of IP Video Surveillance

Scalable deployment based on user needs

Take advantage of wireless and other architectures, and leverage existing IP network equipment

Works with other security systems and has good interoperability with other network devices

Optimize video streams to reduce storage space. Traditional video compression technology requires more storage space.

Wireless technology can be used to distribute video to multiple locations, reducing time and labor costs

Increase security coverage area and improve video transmission quality

Handheld terminals can view video surveillance information at any location and at any time

Faster and more convenient installation, easy to upgrade and migrate

Solution Evaluation

In order to make the most accurate network assessment, several factors are critical, including video compression algorithms, number of cameras, video server locations, and remote viewing locations.

Don't confuse it with NTSC and PAL in analog surveillance. The VGA standard defines the resolution of IP video surveillance. The video compression algorithm determines the video quality, image size, and frame number, and together with the image update technology, it determines the bandwidth requirements for video surveillance. The bandwidth of video surveillance can range from a few hundred KB per second to several megabytes, with a maximum of 30 frames per second for transmission.

To reduce bandwidth consumption, smart cameras and bandwidth optimization features can reduce the size and speed of image transmission, while also considering the bandwidth and latency of remote viewing and PTZ functions. Depending on the camera used, PTZ control latency is generally less than 250ms, and in analog configurations, the encoding/decoding process will take 150-200ms. Remote viewing applications also consume a portion of video transmission bandwidth due to the connection to the video server for monitoring; although managers can access the camera directly. Each manufacturer's remote viewing technology allows users to choose the number of video surveillance cameras to view, camera grouping, resolution, frame rate and PZT control.

In order to fully solve the bandwidth problem, further discussion is needed on devices such as video compression, IP cameras and network video servers.

Video compression method

An uncompressed analog video stream can consume up to 165Mb/s of bandwidth, while a megapixel IP camera can consume several Gb of bandwidth. Therefore, video compression must be used to reduce the image size and reserve more bandwidth.

The degree of compression will affect the quality of RF monitoring, resulting in unclear or distorted video, so a balance must be struck between compressing the video image size and maintaining video clarity. Usually, the solutions of IP video surveillance head and video server manufacturers have already achieved this balance, and the standards that manufacturers can adopt have long been established.

There are currently many compression methods, mainly including H.264, MPEG4 and MJPEG; they can be divided into two categories, namely per-frame compression encoding method and dynamic encoding method.

When considering video compression methods, MJPEG is the most widely used per-frame compression technology, which compresses each video frame completely. This technology allows predictable video demand, but at the same time, MJPEG is not very bandwidth efficient, especially in situations such as foliage movement.

H.263, H.264 and MPEG4 technologies are becoming more and more popular and widely used in video deployments with lower bandwidth and lower image quality. Dynamic compression of all key frames, not all subsequent frames, but frames with changes will be compressed and transmitted. Therefore, the advantage of this technology is that only the parts that change outside the key frame are sent, which can save 50-80% of bandwidth. Strix Access/One adds performance advantages and increases network scalability.

IP Video Surveillance Camera

The current IP cameras not only improve the traditional technology and add network interface, but also make great progress in adopting new analog conversion technology. In the past few years, CMOS technology has promoted the digital-to-analog conversion of low-cost IP video transmission. Progressive scanning better displays moving objects, while analog cameras will have interlaced scanning problems at 4CIF high resolution, resulting in blurred moving objects. Analog video images are composed of lines, and each image is formed by progressive scanning. When the image contains many moving objects, the image will become blurred at the progressive scanning point.

The advanced technology of digital pixel image sampling for IP video surveillance surpasses the traditional analog CCD technology. Through digital pixel image sampling technology, an image can be acquired at one time, providing clear images even in highly mobile situations. The latest pixel image sampling technology supports low brightness and special lighting conditions, fully realizing all the functions of CCD technology. Embedded intelligent algorithms include built-in dynamic discovery, automatic compression selection, bandwidth and network optimization control, and video transmission decision-making process. The new generation of video cameras includes a programmable API interface and DSP, which can be accessed directly or through the NVR's programming interface.

Thus, the PTZ camera can be programmed to recognize an object, zoom in to obtain a high-resolution image and then trigger an alarm, phone call or email to the security personnel. In addition, by entering the megapixel imaging technology, IP cameras can surpass the industry's traditional NTSC/PAL high-resolution solutions. Compared with today's digital/analog cameras (with a pixel count of 400,000), megapixel-level cameras can provide 1 million to 5 million pixel images, and higher pixel levels can be achieved in the future.

New bandwidth optimization technologies, such as frame rate control technology, have become built-in functions, while traditional analog cameras always send all videos. Frame rate control technology for network video surveillance means that IP cameras/video servers only send video at a specific frame rate, and no unnecessary video is transmitted on the network. IP video cameras/video servers can be configured to increase the frame rate after detecting moving targets, or send different frame rates for different receivers, etc. These features are very suitable for remote locations with low bandwidth.

Another important development is VMD (Variable Motion Discovery) technology. VMD is an integrated feature of IP cameras and NVRs that offers many advantages over DVRs. Built into IP cameras or video servers, VMD reduces the load on recording devices and enables event-based video surveillance. When there is no motion in the field of view, no video is sent to the operator or recording device. VMD data about activity information can be included in the video stream to simplify finding activity in storage. VMD can also be located in video management software to provide this functionality for IP cameras that do not have VMD capabilities.

The advantages of VMD functions local to IP cameras and video servers include: saving bandwidth, reducing the CPU load of the recording device, saving storage space, and the camera can cooperate with other systems through input/output ports (for example, triggering alarms).

Based on the above dynamic characteristics, it is very difficult to estimate the bandwidth required for the surveillance system, so the following table lists the general reference for calculating bandwidth based on resolution. In this way, the bandwidth requirement can be determined by simply calculating the image size and multiplying it by the number of frames per second.

Network Video Recorder

Network video recorders are the main components of distributed video surveillance systems and can be located anywhere on the network. NVRs have all the features of today's DVRs, but the essential difference is that NVRs are fully digital systems and are designed specifically for IP video transmission. NVRs allow managers to access, view and control video cameras anywhere on the network.

NVR is basically a software solution that helps end users make hardware decisions, including servers, storage, encoders and decoders, and cameras. NVR can support traditional analog and IP video cameras from multiple manufacturers, including advanced megapixel cameras, and most of them provide advanced programmable interface APIs that can be used for control and customized function development.

The NVR system is a complete digital IP video surveillance system that integrates matrix controllers, switches, control panels and DVRs with storage capabilities into the same system. As a software-based enterprise and video, voice and data management system, NVR provides a graphical user interface, monitoring, recording and analysis functions, providing managers with timely and accurate information.

NVR is the best choice for multi-site monitoring, providing a distributed monitoring system, as well as centralized control of remote installation and offline storage of recorded videos. In a network video monitoring environment, NVR provides recording and video management functions.

Choose an NVR based on the required performance, usually using frames per second as an indicator. If each camera requires 30 frames per second, one server may only be able to record for 25 cameras. If 2 frames per second is sufficient, then one server can manage 300 cameras. This means that the system performance is fully utilized and optimized.

For large deployments, IP network video systems are the easiest to expand. When the system needs to support high frame rates or longer video frames, it can be done by adding processor capacity and memory to the network video server. Or a simpler way is to add another NVR device, which can be located at the central site or at a remote site.

IP video surveillance cameras perform encoding functions, or analog cameras can work with independent encoding/decoding devices. NVRs can be placed anywhere in the network. Physical independence from encoding devices simplifies management and improves availability. NVRs do not need to contribute system processing power to manage video cards or compression. NVRs provide video stream management and video storage management. It cannot be ignored that storage management is also a very important factor to meet users' storage requirements for 24-hour recording. NVRs can edit stored videos based on dynamic or other criteria, further reducing daily maintenance work and potentially reducing the need for video storage capacity.

Today, governments and enterprises maintain multiple independent servers for remote DVRs; when using NVRs deployed anywhere in the network, centralized management of remote database videos becomes much simpler, and remote databases can be replicated to the central security room. Separating the video surveillance function also helps improve work efficiency. While maintaining the servers of other key business systems, the IT department can assume the responsibility of maintaining video surveillance servers and storage, ensuring that edge video devices can be stably connected to the network, and servers can also be regularly maintained to provide the ability to continuously monitor network assets.

In addition, the IT department provides reasonable access to resources according to security policies, so that security personnel can focus on security events rather than maintaining storage devices. As a result, not only is the duplication of equipment investment for network transmission and video access reduced, but also the organizational roles and responsibilities are optimized. The fully distributed capabilities of NVR are very suitable for cooperation with wireless Mesh networks, further reducing the initial equipment deployment costs and post-use operating costs.

Strix high-performance Mesh architecture significantly reduces the cost of intelligent residential areas

Strix Access/One multimode products are designed for high performance and flexibility. Strix's patented multimode portfolio includes standards-based 2.4GHz 802.11b/g, 5GHz 802.11a and high-power 4.9GHz DSRC-C for public safety networks, providing the industry's first "any module, any service and any configuration" flexibility support.

Strix Access/One adopts the powerful and stable Strix Dynamic Mesh Architecture (DMA), and implements the Strix High Performance Mesh Algorithm (HPMA) and Scalable Mesh Fast Re-route (SMFR). Strix DMA solves the problems existing in other Mesh algorithms, and SMFR provides automatic self-organizing, self-healing, and fast routing regardless of topology, supports mobile roaming under high-speed movement, and near-zero bandwidth loss after multiple hops.

Strix Access/One is the industry's most cost-effective wireless mesh platform, delivering a total cost per square kilometer (TCO) that is three times that of other systems. The platform supports one fiber node with 100 wireless mesh nodes, covering 10 square kilometers, greatly reducing site coordination time, costs and complexity, accelerating the time to market for services, and helping to achieve the industry's lowest total cost of ownership.

The industry's only modular system: provides the highest capacity, highest throughput and lowest latency, supporting voice, data and video applications. Strix OWS outdoor wireless mesh nodes support field upgrades, up to 6 wireless modules, and support a wide range of antenna options; up to 4 wireless modules can be used for customer access, greatly improving indoor penetration (using sector antennas) and increasing user density by 3 times. In addition, the introduction of new technologies, such as WiMAX, is easier to achieve through field upgrades.

The Strix platform has been deployed in more than 100 metropolitan areas around the world and has been verified by Iometrix independent laboratories. The system is mature and stable and has been widely verified. These tests have shown that Strix is ​​the industry's best-performing wireless mesh network platform, maintaining a high throughput of 35Mb/s after multiple hops. In addition, the mobile switching time at a speed of 300 kilometers per hour is less than 50ms, making high-speed mobility such as railway deployment possible.

The platform's zero-configuration scalability meets the needs of city-level or even national-level wireless mesh network deployment. Management is simple, Strix provides a graphical management interface and command line commands to quickly obtain system working status. The product provides hardware-accelerated AES encryption to protect communications between wireless nodes, and uses WPA for terminal access security.

Distributed video surveillance systems are an important means of residential security, and the Strix distributed wireless surveillance network brings great value to similar deployments.

Strix wireless mesh network provides performance and flexibility comparable to wired networks, which is very suitable for video surveillance in residential areas, and can be coordinated with intelligent community security such as alarm, access control, and boundary systems.

Rapid deployment method

1) Powering Mesh nodes and cameras

Install Strix Mesh nodes indoors or outdoors

Each Mesh node supports multiple video cameras, and the Mesh nodes are connected via network cables. Outdoors, it can support solar power supply

2) Determine the minimum number of fiber optic landing points required for the wireless mesh network

Determine the number and location of cameras and calculate the required bandwidth

First determine the location of the camera and the video surveillance center equipment, and then determine the location of the Mesh node

In large deployments, the maximum bandwidth of the cameras must be considered and used to calculate the overall bandwidth.

For redundancy purposes, a certain number of fiber landing points and wireless Mesh nodes need to be added

3) Implement VLAN on the path between the video camera and NVR/DVR, implement QoS to ensure high throughput and low latency to the central node, and use Strix high-performance wireless backhaul links for traffic relay when there are blind spots

4) After power-on, the Strix Access/One nodes will automatically form a wireless Mesh network to complete the network networking work

In summary, the multi-mode Mesh solution not only brings about performance improvements, but also has a far-reaching impact on the intelligent construction of wireless video surveillance in residential areas due to the improved cost-effectiveness of the metropolitan area Mesh network.