TrellisWare offers several products for better characterizing RF environments. Typically referred to as situational awareness features, these processing products work “blindly”—without prior knowledge of the transmitted signals or details of the surrounding physical environments.
TrellisWare’s situational awareness solutions work where traditional methods fail—in bad multipath and dynamics, where significant interference exists, in low SNR and/or Doppler degradation, with short record lengths, and without specific information on timing or geometry.
TrellisWare has designed Direction Finding (DF) products for customer-identified signal types and our algorithms allow for the discrimination of more angles of arrival (AOA) than antennas used. The algorithms work from very short records of data or, equivalently, in very high noise environments. TrellisWare’s DF algorithms can derive multiple reflections of single signal sources even in very high multipath environments such as urban or enclosed areas and in the presence of substantial RF interference – conditions where typical DF approaches completely fail. Unlike conventional matrix-based DF approaches, TrellisWare’s approach exploits the time-domain structure of the signal of interest (SOI) as well as the intervening channel profile in order to estimate the position-related parameters of the SOI. This allows TrellisWare to perform DF processing in the midst of bad reflections and at very low SNR’s (or very short measurements).
TrellisWare’s situational awareness products can be used to test the RF environment in support of cognitive radio, detect and avoid (DAA), interference mitigation, or applications requiring location/direction of a signal relative to the receiver. They can also be used to map the location of signals in the immediate surroundings or better optimize a receiver’s performance based on other signals with which it must compete. In addition to using these algorithms in our own products, TrellisWare offers customized solutions for customer systems and applications as FPGA cores and/or software.
Multi-User Signal Separation
In many scenarios, the collected signals overlap in time and frequency and must be separated. This can be accomplished by exploiting differences in the signals such as different propagation channels and different signal encoding. In the absence of beamforming, users are separated via Single-Antenna Interference Cancellation (SAIC) techniques. TrellisWare has developed innovative SAIC solutions that reside in the digital baseband processing section of the receiver and allow handsets to operate under very strong interference conditions. These techniques have also been applied in SIGINT collections with great success. Again, the underlying framework is TrellisWare Likelihood Processing (TLP) and joint signal modeling. The TrellisWare SAIC Equalizer can either be implemented fully in hardware, fully in software, or partitioned into a hybrid hardware/software implementation. TrellisWare has developed, in parallel, multi-antenna solutions for this co-channel interference mitigation problem. This allows spatial features (angle of arrival) to be combined in TLP with time-domain properties for even greater gains.
Strong Interference Mitigation
Interference mitigation is needed in many military situations (jamming) or large adjacent-channel non-white interference. Here, the interferer must be estimated with accuracy during demodulation in order to cancel out its effect. This can be done either extraneously in a companion interference-cancelling unit or sub-merged in the joint trellis processing at the receiver. TrellisWare has developed a variety of solutions ranging from passive non-linear cancellation to active-adaptive interference cancellation, enabling practical cancellation of interference that is several orders of magnitude stronger than the signal of interest.
Key features of our SA Products
- System-parameter agnostic (autonomously estimates signal BW, baud rate, synch, SNR)
- Blind operation (non-data-aided)
- Suited for high-order modulations (e.g., QAM)
- Suited for challenging channels and short records
- Symbol-stream demodulation a side benefit
- Extendable to array reception
- Demonstration with easy-to-use GUI