The NXDN® Digital Advantage
In analog systems as the signal strength decreases in low-coverage areas, noise and dropouts increase, severely degrading intelligibility. However, with the NXDN® digital system, which features enhanced Forward Error Correction (FEC), the digitized audio stream is less susceptible to noise, resulting in superior clarity at varying signal strengths. System operators converting from analog to NEXEDGE® typically comment that users now receive calls in areas that were out of range before. NXDN® reduces lost or misinterpreted calls and the need for repeat calls, thus enhancing workforce productivity.
In analog systems as the signal strength decreases in low-coverage areas, noise and dropouts increase, severely degrading intelligibility. However, with the NXDN® digital system, which features enhanced Forward Error Correction (FEC), the digitized audio stream is less susceptible to noise, resulting in superior clarity at varying signal strengths. System operators converting from analog to NEXEDGE® typically comment that users now receive calls in areas that were out of range before. NXDN® reduces lost or misinterpreted calls and the need for repeat calls, thus enhancing workforce productivity.
NXDN®
A key element of the NXDN® air interface is the AMBE+2™ vocoder which digitizes speech while retaining natural voice nuances, performs noise reduction, introduces FEC and compresses this voice data to accommodate land mobile radio data rates. Next, the radio's digital signal processor (DSP) protocol- packages the vocoder, signaling, control, and more FEC data together and converts this to a uniquely filtered 4-Level FSK digital waveform that modulates the transmitter. This results in an unusually low bit-error-rate digital air interface delivering robust communications even in weak signal strength areas. The NXDN® air interface is capable of fitting into both narrow 12.5 kHz and very narrow 6.25 kHz bandwidth channels meeting the tightest of spectrum efficiency requirements (9600 bps @ 8.3 kHz and 4800 bps @ 4 kHz occupied bandwidth respectively). NXDN® is a Frequency Division Multiple Access (FDMA) methodology whereby one user accesses a channel frequency at any one point in time (i.e. accesses via the frequency domain). Other digital methods such as Time Division Multiple Access (TDMA) permit more than one user to access the channel frequency via timeslots (i.e. accesses via the time domain), but there has to be a tradeoff between coverage and effective transmission rate, as increasing the former means decreasing the latter.
A key element of the NXDN® air interface is the AMBE+2™ vocoder which digitizes speech while retaining natural voice nuances, performs noise reduction, introduces FEC and compresses this voice data to accommodate land mobile radio data rates. Next, the radio's digital signal processor (DSP) protocol- packages the vocoder, signaling, control, and more FEC data together and converts this to a uniquely filtered 4-Level FSK digital waveform that modulates the transmitter. This results in an unusually low bit-error-rate digital air interface delivering robust communications even in weak signal strength areas. The NXDN® air interface is capable of fitting into both narrow 12.5 kHz and very narrow 6.25 kHz bandwidth channels meeting the tightest of spectrum efficiency requirements (9600 bps @ 8.3 kHz and 4800 bps @ 4 kHz occupied bandwidth respectively). NXDN® is a Frequency Division Multiple Access (FDMA) methodology whereby one user accesses a channel frequency at any one point in time (i.e. accesses via the frequency domain). Other digital methods such as Time Division Multiple Access (TDMA) permit more than one user to access the channel frequency via timeslots (i.e. accesses via the time domain), but there has to be a tradeoff between coverage and effective transmission rate, as increasing the former means decreasing the latter.
Spectrum Efficient
All NEXEDGE® equipment operates in 25 & 12.5 kHz analog and 12.5 & 6.25 kHz NXDN® digital modes – satisfying spectrum requirements today & tomorrow.
All NEXEDGE® equipment operates in 25 & 12.5 kHz analog and 12.5 & 6.25 kHz NXDN® digital modes – satisfying spectrum requirements today & tomorrow.
Migration by Design
NEXEDGE® extends the life of current radio system assets. All NXDN® digital modes use the same Class-C power amplifiers and site management equipment used for current analog stations, ensuring return on investment (ROI) and a multitude of supplier choices. Current analog and NXDN® digital fleets can share a NEXEDGE® base/repeater station in 12.5 kHz conventional "Mixed Mode," thus providing uninterrupted service as long as needed and a straightforward migration path as aging analog fleets are replaced with digital. Also, NEXEDGE® trunked traffic channels can be shared with existing external analog conventional or trunked logic controllers, extending service to fleets as a transition to NXDN® trunking is underway.
NEXEDGE® extends the life of current radio system assets. All NXDN® digital modes use the same Class-C power amplifiers and site management equipment used for current analog stations, ensuring return on investment (ROI) and a multitude of supplier choices. Current analog and NXDN® digital fleets can share a NEXEDGE® base/repeater station in 12.5 kHz conventional "Mixed Mode," thus providing uninterrupted service as long as needed and a straightforward migration path as aging analog fleets are replaced with digital. Also, NEXEDGE® trunked traffic channels can be shared with existing external analog conventional or trunked logic controllers, extending service to fleets as a transition to NXDN® trunking is underway.
Variety of Operation
NEXEDGE® systems are configurable in traditional conventional, trunked and wide area trunked network operation modes. IP connectivity for NEXEDGE® trunked sites provides scalability over existing LAN/WAN assets and services.
Outstanding Voice Quality
The AMBE+2™ Vocoder is a state-of-the-art voice compression digitization technology that offers superior clarity at varying signal strengths, even at highway speeds.
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