Access to surveillance data, outside the surveillance network, is an integral element of the security architecture of all Homeland Security implementations. The importance of widespread authorized access lies in the crucial role it plays in meeting the vital information needs of public safety officials (police officers, medical teams, dispatchers, etc.) during homeland security emergencies.
Reliability and data security are the two crucial aspects of such access and this article enumerates the various backhaul options available in India, for transmission of surveillance feeds.
ADSL
The standard wired broadband technology used in most areas, in India, is Asymmetric Digital Subscriber Line (ADSL). Newer technologies in use include VDSL and pushing optical fiber connections closer to the subscriber. ADSL technology is asymmetric and allows more bandwidth downstream (downlink) than upstream (uplink). The asymmetry, combined with always-on access makes ADSL ideal for Internet/intranet surfing, video-on-demand, and remote LAN access: users of these applications typically download much more information than they send. This solution is ideal for low-bandwidth surveillance transmission where the on-site recording and storage equipment is stationary and web-enabled; and the central control station is able to access the stored or real-time data over a browser.
WiMAX
WiMAX (Worldwide Interoperability for Microwave Access) is a standards-based technology that delivers last mile wireless broadband access, as an alternative to cable and DSL. WiMAX provides broadband wireless access (BWA) up to 50 km for fixed stations, and 15 km for mobile stations.
The current WiMAX revision provides up to 40 Mbit/s with the IEEE 802.16m update expected to offer up to 1 Gbit/s fixed speeds. WiMAX positions itself as a credible alternative, to wired backbones, for high-bandwidth transmission of real-time video surveillance. As a wireless WAN technology, WiMAX has been designed specifically with the efficient backhaul of broadband data, voice and video at its core. However, in its implementation WiMAX data rates have been far lower than the stated figures, and successful practical implementations of high-bandwidth WiMAX backhaul are yet to be demonstrated.
4G
“Fourth Generation wireless telecommunication technology” or 4G, is an advanced radio communication technology which provides a union of high-speed internet access and high-quality mobile telephony. The technology enables simultaneous voice and non-voice data transfer. 4G is expected to provide a comprehensive and secure all-IP based solution where facilities such as IP telephony, ultra-broadband Internet access, gaming services, and streamed multimedia can be provided to users. The most widely implemented standard will be LTE (Long Term Evolution) Advanced, although WiMAX too is positioned as a 4G standard. Depending on the equipment category, LTE provides downlink peak rates of up to 300 Mbits per second and an uplink peak rate of 75 Mbits per second. LTE Advanced will be able to further delivers peak downstream rates of up to 1 Gbits per second for low mobility requirements and 100 Mbps for high-mobility requirements.LTE networks are just about being deployed in Europe and the USA. However, in India 3G is just about being rolled out, and 4G roll-outs are at least of couple of years away. Until such time the cellphone infrastructure will be unable to handle the high-bandwidth requirements of real-time video surveillance.
Proprietary OFDM/COFDM
Orthogonal Frequency Division Multiplexing (OFDM) - which is also used in LTE, WiMAX, and the popular Wi-fi standards - is a method of digital modulation in which the signal is split into several narrow-band channels at different frequencies. OFDM has developed into a popular technology for wideband digital communication, and is used in applications such as digital television and audio broadcasting, wireless networking and broadband internet access. COFDM stands for Coded OFDM, where the data transmitted on the narrow-band channels is protected by Forward Error Correction (FEC) coding.
OFDM provides a bandwidth of between 125-300 Mbps over a distance of up to 200 km. The OFDM technology is ideal for enabling city-wide surveillance for both high scale in-city surveillance and wide area security projects including: traffic surveillance, airports, border control, railways, seaports and gas and oil pipelines. OFDM based Point-to-Point (PtP) and Point-to-Multipoint (PtMP) architecture successfully meet high-quality security project requirements, simply and quickly, and with optimal results. Proprietary OFDM based solutions are available from vendors like Motorola, Proxim Wireless, Cobham, Smartbridges etc., and can be used for setting up high-bandwidth backhauls until such bandwidth is available from public networks.
Proprietary Wi-fi
In addition to the above, there are a range of high-capacity wireless Ethernet solutions currently available in the market. These are designed for maximizing performance, scalability, mobility and ease of deployment, and can operate in 2.4 GHz, 4.9 GHz or 5 GHz spectra. These solutions can be used to create PtP, PtMP and Mesh architectures that can be deployed anywhere, creating secure and reliable wireless networks for video, voice and data transmission.
These solutions are available from vendors like Firetide, Fluidmesh, Meraki, Strix Systems etc.
Conclusion
From transporting two-way radios voice traffic to streaming on-scene video, a backhaul is a critical operation in the overall communications network – and has to perform flawlessly. Keeping in view the stretched budgets and limited resources, an ideal solution would be one that provides the bandwidth and reliability needed to backhaul critical data, voice and video feed to a control center to aid in decision making for critical and emergency situations; while offering maximum value and cost efficiency.