NECTAR SDR TECHNOLOGY INITIATIVE

With the penetration of mobile telephony, the Internet, e-applications and related products, it would seem that communication across the world between any two nodes or persons is no longer a problem. This is generally true, but the claim is rendered short in times of crises and disasters with widespread network and communication failures and power breakdowns. Or when large organizations and entities with critical operations, or those responsible for disaster management, for security, law and order and surveillance operations seek wholly owned networks which are mission critical, fail safe, secure and unaffected by crises or disasters.

The multiplicity of radio equipment with different organizations, led to a situation where interconnectivity between organizations could not be established. Use of different bands and equipment was a major bottleneck for joint operations. Therefore, the United States Govt. initiated the joint tactical radio programme so that sets operating on different bandwidths could connect with each other. As a consequence, the Software Defined Radios with 99 % digital signal communications were developed so that this cross communication between organizations was possible and these sets could also talk to legacy equipment.

Key Features of the SDR Communication Platform:

  • Dedicated network for law enforcement and government agencies provides a seamless communications backbone
  • Supports AM, FM, SSB, CW, Packet Radio on HF and OFDM to 64QAM, IEEE802.11a/b/g and other high ECC and efficient protocols capable of 300 Mbps data transfer rates at 5Ghz
  • Deployable in both urban and rural scenarios
  • QoS for Voice & Video
  • High Security using AES
  • Node range of 3-6Kms, HF Radio range over 300Kms. Using appropriate aerials the range can be increased to communicate across India.
  • Compatible with all legacy modulation schemes used on HF
  • Digital Voice transmission capability on HF

A Software-Defined Radio (SDR) refers to the technology wherein software modules running on a generic hardware platform consisting of DSPs and general purpose microprocessors are used to implement radio functions such as generation of transmitted signal (modulation) at transmitter and tuning/detection of received radio signal (demodulation) at receiver.

Benefits

  • Capacity to be deployed over a wider temperature/environmental range due to fewer analogue components. The digital circuitry is not affected to the same extent by temperature/pressure/humidity.
  • Thus there is a higher order gain with the SDR as compared to the existing wireless communication equipment and technology. It enables encrypted data transfer, simultaneous data and voice transmission, sharp filtering, active pre-distortion and feature change by software upgrades that does not require complete overhaul of hardware.
  • SDRs allow for use of Digital Signal Processing such as Noise reduction, Noise blanking and various other filtering modes enhancing the receiver capability.
  • Implementation of pre-distortion capability in SDRs allows for about 100 times lower distortion than legacy radios. This not only allows for cleaner transmitted output but enables faster data throughput.

Deployment of SDRs

The Software Defined Radios (SDRs) can be deployed in three modes:

  • They can be established as base stations to provide a State wide or a Country wide network. This forms the core of the communication network.
  • Vehicle Mounted SDRs can be used to link the base stations to the Mobile platform as well as provide intercommunication between the mobile platforms.
  • Two variants of the man pack have been designed. The first variant meets Penta-5 regulations thereby making the set a military grade equipment. The Second variant is housed in a splash proof housing with an appropriately designed back pack to prevent effect of moisture on the equipment.
  • The SDR sets can also be linked to leased lines used by various government services, messages received via HF email system or via leased line can be forwarded using either systems, hence providing complete integration.