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sharma Enabling High Quality Video Surveillance Over an All-IP Wireless Network
By Ashish Sharma, Vice President, Marketing • Alvarion

As security takes center stage in today’s society, technology innovation in real-time surveillance systems becomes very important, spurring the development of new capabilities. There are a multitude of markets that utilize surveillance systems including commercial buildings, malls, housing complexes, high traffic metro areas, cities, municipalities and transportation. While video surveillance has traditionally been deployed primarily using the existing fixed line technologies, due to overdependence on the legacy infrastructure, new long range wireless technologies such as WiMAX are introducing capabilities that significantly enhance the reach of existing networks. The advent of OFDMA technology coupled with advanced antenna technologies such as Multiple Input Multiple Output (MIMO) and Beamforming have enabled significant improvements in radio performance which makes wireless broadband an attractive building block for high capacity video surveillance networks.

Wireless Creates New Opportunities
As all-IP wireless broadband networks are built, many new technology functionalities come to the forefront, enabling a variety of applications. As these networks are based on packet based communication, the cost economics as well as the ease of new service introduction is becoming increasingly optimized.

The 4G WiMAX technology based on the IEEE standard 802.16e possesses the features and attributes necessary to meet the cost, performance and coverage demands required for a wide area cost-effective, all-inclusive video surveillance system.

Wireless broadband networks complement existing wired infrastructure, and can be utilized as new infrastructure for video surveillance deployments. Wireless network infrastructure helps overcome many challenges, such as: limited or lack of wired reach; time consuming deployment; limited flexibility for changes and rerouting; high deployment costs (CAPEX); and high operating costs (OPEX).

4G WiMAX Provides an Optimal Solution
4G WiMAX technology has several attributes and features that make it an attractive and cost-effective solution for high performance video surveillance networks.

Support for OFDMA and advanced antenna techniques such as MIMO and Maximum Ratio Combining (MRC), a WiMAX base station can provide the non-line-of-sight (NLOS) range to economically extend coverage beyond existing wireline facilities and provide a line-of-sight (LOS) range up to 25 km in a Point-to-Multipoint topology.
Interference mitigation techniques such as Hybrid Automatic Repeat Request (HARQ) and Media Access Protocol Signaling (MAPS) repetition to ensure good performance in license-exempt bands.
Support for channel bandwidths up to 20 MHz (2 X10) to support multiple remote sites with high quality video and other broadband services.
Quality of service support for multiple applications to enable voice, data and video traffic over the same link.
Advanced security techniques to ensure communications confidentiality.
Support for a high upstream data rate for high quality video surveillance images.
Multi-casting functionality that saves bandwidth by avoiding multiple transmission of the same video stream to different users.
WiMAX is built on an all-IP backbone to enable easy integration and interoperability with a wide range of readily available off-the-shelf devices and systems.
WiMAX deployments can be implemented in a variety of topologies, including Point-to-Point, Point-to-Multipoint or mesh, thus offering considerable flexibility in the design and optimization of a wide area broadband network.
WiMAX can be used to backhaul Wi-Fi access points for additional local area coverage.

Optimizing Video Over Wireless
Wireless connectivity offers video surveillance solutions the combination of reduced deployment costs, flexibility and scalability in the placement of cameras and optimization of bandwidth allocation.

However, a wireless solution may also be sensitive to interference caused by other radio transmissions. In a licensed-exempt environment the issue of interference is more challenging as the same frequency is being shared by multiple devices operated by non-synchronized operators, serving different customers and applications. Such interfaces can cause significant performance reduction of the wireless link and reduce video quality.

Alvarion offers a software client that resides at the Subscriber Unit (SU) for enhancing video quality performance in a challenging wireless link environment. The software client utilizes a sophisticated algorithm which analyzes the wireless link status and the video stream characteristics. In addition, the video stream is adjusted via the dedicated algorithm and transferred in a unique sequence maximizing the video stream transmission’s efficiency and reliability.

HARQ, a state of the art error control method algorithm, is also part of the embedded software. This method outperforms other methods in poor signal conditions, by storing incorrectly received coded data blocks at the receiver (rather than discarding them), and when the retransmitted block is received, the two blocks are combined (often referred to as Chase combining) for correct data extraction with significantly higher probability to receive a correct packet.

Video quality is significantly improved in challenging wireless conditions as the embedded algorithm enhances video streaming continuity in a changing wireless link conditions environment, enabling recording systems to continue recording the video stream.

Camera Power Feeding
Wireless deployment reduces CAPEX and OPEX significantly when comparing the deployment costs of alternative infrastructure solutions. Wireless eliminates the need for high cost trenching; additionally, in license-exempt deployments, the expensive fees for owning a frequency license are avoided.

Though deployment costs are low when comparing to a wired deployment, it is important to seek additional value-add- features to both reduce costs and facilitate installation. For instance, a subscriber unit dedicated for wireless video deployments (SU-V), supporting upstream bandwidth with minimal downstream will cost effectively support video application. The SU-V can be supported with an external easy to install Video Power Supply (VPS) unit, providing power to an IP camera while connecting the camera to the outdoor SU-V. The 802.3af standard is used to power feed cameras that support compatible cameras.

As illustrated here, one single AC power cable is connected to the VPS, from which the power is distributed to both the SU-V and the camera. The accessory is also supporting the IP connectivity between the SU-V and the camera.

Optimized asymmetric bandwidth allocation dedicated to video streaming needs along with the camera power feeding accessory provides a cost effective quick and quality driven solution.

The VPS accessory enables rapid and easy installation with a major saving per installation, as the entire connectivity is outdoor using a single power cable feeding the system.

Wireless Point-to-Point Link
Wireless Point-to-Point links support up to 60 Km distance connectivity, while maintaining very low costs. Such links are easily installed by experienced wireless installers. In recent years the cost effective, reliable and ad-hoc wireless solutions are becoming extremely popular, and demand is increasing for a system that can be quickly installed and deployed by non-experienced wireless installers.

Point-to-Point solutions are available in different configurations supporting up to 250 Mbps.

Alvarion has invested in delivering a plug and play solution targeted to all installers including those with only analog camera installation experience. Alvarion offers a 10 Mbps wireless robust and secured Point-to-Point link to backhaul video surveillance cameras. The link is set up with a user friendly GUI wizard to set the basic parameters. The solution maximizes the wireless link throughput by automatically configuring the wireless parameters to best fit the environmental link status, minimum user intervention.

The Alvarion Point-to-Point wireless link provides:

Automatic clear channel selection
Activation of enhanced interference mitigation algorithms
Automatic adaptive modulation for noisy environment
Automatic adjustment of asymmetric link UL/DL ration

Wireless Multicasting
Video surveillance deployments allow for real-time monitoring from a central office. Allowing multiple mobile vehicles and terminals to view real-time video streams so that they can react rapidly and appropriately to emergency situations not only requires wireless solutions, but also requires a method that can transport the data efficiently.

The quality of service WiMAX 802.16e network can serve the upstream from the video cameras to the video server as well as the video broadcasted to the vehicles. The ability to multicast quality real-time video streams to multiple subscribers reduces the cost of the solution as less base stations are required to support the application. The personnel in the vehicles see the video feed and may respond accordingly, before arriving at the scene.

Alvarion’s BreezeMAX Extreme solution is customized for video surveillance applications. This solution is WiMAX 802.16e compliant and available at licensed-exempt frequency bands for an attractive and easy rollout.

As the demand for security increases and technology innovation constantly evolves, future-proof, real-time surveillance systems will continue to be very important for a multitude of markets including commercial, residential, municipalities and transportation.

As VP of Marketing for Alvarion Ltd., Ashish Sharma is responsible for many aspects of worldwide corporate marketing activities where he manages media and analyst relations and serves as the company spokesperson. In addition, he leads corporate market development efforts for several key regional markets for Alvarion. Sharma is quite active within the WiMAX industry and plays a prominent role within the WiMAX Forum Marketing Working Group. Sharma has been instrumental in developing the WiMAX industry early on and has contributed to the growth of the industry leading key activities both with Alvarion and the WiMAX Forum.