Technology Section 940x180 overview Cognitive Radio Networking Network Architecture xMax Physical Layer xMAC: Low Latency MAC Optimized Mobile VoIP

Interference Mitigation

xMax: Industry Leading Interference Mitigation

As most people know, interference works against reliable and efficient wireless communications. Interference can negatively impact performance and coverage, and is the chief limiting factor in high-capacity mobile systems. interference is responsible in many cases for dropped calls, slow download speeds and shortened battery life

While interference has been an issue in the unlicensed spectrum bands for years, mobile carriers are seeing that their licensed (i.e. dedicated) spectrum used in 3G and 4G mobile networks are also experiencing unprecedented levels of interference. In addition to commercial networks, interference is also of concern to our public safety, armed forces and homeland security agencies. Their growing reliance on broadband communications makes unintentional and intentional interference (jamming) a real threat to their missions.

xMax leverages proprietary xG developed technology to implement two key approaches to dealing with interference.

The first is Dynamic Spectrum Access (DSA). xMax uses its real time sensing of interference on a channel to instantly change channels when better frequencies are detected. However, xMax goes beyond simple DSA by incorporating sophisticated interference mitigation (IM) software that enables xMax to reliably operate on interference laden channels that other radio systems could not operate on. When xG’s interference mitigation technology is added to its DSA capabilities, xMax can greatly increase the capacity of both new and existing spectrum assets.

The xMax radios employ new and powerful parallel processing digital signal processers and computer processing units (DSP/CPU) that support speeds up to 50 Giga OPS (billion operations per second) for signal processing. This capable processor, combined with 2x4 MIMO antenna configurations, enables the xMax system to use patent-pending spatial processing software to remove unwanted interference from the target xMax signals. Each xMax cognitive radio can simultaneously mitigate up to 24 mobile sources of interference or jamming. By using xMax’s multi antenna technology to separate unwanted interference from desired xMax signals, xG is able to offer robust and reliable links in conditions that would cause other radio systems to completely fail.

MIMO interference mitigation image

Figure 1

xMax MIMO Based Interference Mitigation Separates Interference from Desired Signals

By enabling xMax to tolerate high levels of interference before requiring the radios to switch channels, more “gray spectrum” (containing interference or jamming) can be used in place of scarce “white spectrum” (clean and interference-free). This makes white spectrum channels available for other radios that cannot effectively mitigate interference. This capability increases the xMax network’s total throughput and capacity greatly – without consuming additional scarce and costly spectrum resources.


For more on xG’s interference mitigation technology, click here for a our technical overview document