Products & Applications

Wifi

Wireless Infrastructure

5G Mobile Devices

Test Equipment

Wi-Fi

Elevating Wi-Fi data rates with wider bandwidth and higher modulation rates

  • Support 2.6 Gbps per MIMO layer with 4096QAM @EVM -44dB
  • Support 160MHz
  • Improve PA power output and efficiency
  • See latest 160MHz 802.11ax test results on commercial amplifiers

The latest generation of Wi-Fi such as 802.11ax are specifying bandwidths of 160 MHz as well as higher modulation schemes such as 1024 QAM (10-bits/symbol Quadrature Amplitude Modulation).   Wider bandwidth and higher modulation rates lead to higher data throughput and greater spectral efficiency.  However, the critical challenge of 1024 QAM or 4096 QAM (also under consideration) is to achieve these higher rates at usable distances. Without an innovation or breakthrough, these rates would appear on a Wi-Fi Box as “eye candy”, but would be difficult to achieve in the real-world environment with usable distances. NanoSemi’s Linearization is that breakthrough providing improved rates at usable distances.

Non-linear components result in degraded signals and transmitter performance.  Signal cleanliness is measured by the Error Vector Magnitude (EVM) with a smaller value corresponding to a cleaner signal.  The figure below shows an uncorrected 160 MHz 802.11ax signal compared to a corrected, NanoSemi linearized version. Notice how the 20 dB EVM improvement results in a signal with a cleaner constellation.

NanoSemi’s linearization improves the signal with higher amplifier power and efficiency.   Higher data rates are achieved at any given range and the improved PA efficiency results in lower battery / power consumption.

NanoSemi has conducted a series of 802.11ax waveforms testing on commercially available, Wi-Fi grade power amplifiers from Skyworks.  Test results here.

For more details on Wi-Fi improvements, please see the white paper here.

NanoSemi’s Wi-Fi Linearization Solution improves the signal constellation, allowing for higher order modulation.  The diagram on the left is an 802.11ax 160MHz signal without any linearization.  The diagram on the right shows the same signal processed with NanoSemi’s linearization solution using a typical Wi-Fi power amplifier. The improved EVM allows for 4096 QAM at output power of 24dBm with 160MHz signal bandwidth.

NanoSemi’s Wi-Fi Linearization Solution improves both Power Output and EVM, yielding better rate to range performance due to higher power output and better EVM performance (free space propagation model)

Wireless Infrastructure

Enabling wideband, power efficient LTE and 5G Base-stations

 

  • Linearize bandwidth in excess of 100MHz for 4.5G and 5G
  • Meet or exceed 3GPP base-station ACLR specifications
  • Support dual band radio deployments
  • Reduce Passive Intermodulation Interference

TDD systems are demanding increasingly wideband solutions with bandwidth exceeding 80 MHz as more contiguous spectrum is available, i.e. wideband spectrum available in bands 42 and 48 (3.5 GHz).  These wideband LTE wave forms are also required to meet stringent performance metrics.   Specifically, 3GPP puts constraints on adjacent channel performance measured by the Adjacent Channel Leakage Ratio (ACLR), which is defined as the ratio of the transmitted power to the power in the adjacent radio channel.

NanoSemi’s Linearization enables 4G and 5G base-stations in excess of 100MHz. NanoSemi’s implementation is inherently broadband and can meet the ACLR specifications at wider bandwidth while concurrently improving PA efficiency and power output.  As can be seen in the figure below, a 25dB ACLR improvement over 200MHz is achieved, meeting the 3GPP ACLR specification.

ACLR improvement of 25dB in a 200MHz OFDMA waveform (10x20MHz LTE). This is also indicative of a 2X100MHz 5G waveform.

In addition, as a step towards the evolution to 5G base-stations, 4.5G systems are applying LTE waveforms to massive MIMO radio front ends with up to 64 PA chains.  NanoSemi is able to improve the power efficiency of every PA chain. In addition, our implementation is able to share one receiver (either from a dedicated observation path or a regular receiver channel) among multiple transmitter channels, a capability becoming increasingly important for large MIMO implementations.  The combination of greater power efficiency, lower power consumption and the feedback receiver sharing significantly reduces the radio subsystem power consumption.

5G-NR waveforms (still being finalized in 3GPP) are very broadband, with component carriers that are 100MHz wide vs. 20MHz for 4G LTE.  Thus, broadband operation in multiples of 100MHz is required by both mobile devices and base-stations.  5G is anticipated to operate at both mmW bands (28GHz and 39GHz) and Sub 6GHz (e.g. 3.5 GHz) and in the case of mmW extreme bandwidths of 800MHz are expected.  Traditional approaches to linearization such as DPD using generalized memory polynomials become increasing complex as bandwidth scales. NanoSemi’s linearization is able to address these broadband signals at significantly reduced complexity and power consumption.

 

 

Wideband linearization benefits to 5G basestations
Sub 6 GHz mmW
Wideband (>=100MHz) Wideband (800MHz)
Compensates GaN and LDMOS PA Boosts GaAs/CMOS PA output power
Improves power efficiency Improves power efficiency
3-5x lower power in ASIC implementation Beam-steering adaptation
2-3x smaller in FPGA resources Low power architecture

NanoSemi’s wideband linearization also enables the combination of two transmit chains into a single Tx architecture and hardware, thereby reducing the cost of power amplifiers, antennas and tower space. A dual band solution based upon NanoSemi’s Linearization can reduce the cost of remote radio head components by 40% or more.  The key is enable the transmit chains to implement very wideband signals while still meeting 3GPP ACLR specs and not desensitizing the receivers.

The key to enabling this is suppression of the nonlinear products between the band 1 and  band 3 transmit output as shown in the diagram below:

Passive Inter-Modulation (PIM) products are caused by passive components such as duplexers, connectors, cables, and antennas. These components are nonlinear and create intermodulation products that can leak into the receive path of a FDD system. Also, duplexers used in FDD systems have a limited isolation between transmitters and receivers. These intermodulation products will appear as distortion and noise in the receiver.

 

In addition, there are external sources of PIM Interference.  A base-station located near any structure with rusty components can create intermodulation products as the rusty elements act as nonlinear transmitters.  This can create unwanted signals in the base -station receiver as can be seen in the figure below.

NanoSemi’s Linearization algorithms can remove all these causes of PIM by characterizing the non-linearities and removing the products in the receive path.   Models of the internal causes of PIM are created and “subtracted” from the receiver signal.  In addition, a receiver can be used to sample the signal and estimate the causes of PIM from external components and subtract them from the receive path.

5G Mobile Devices

Enabling 5G Mobile Devices

5G-NR waveforms (still being finalized in 3GPP) are very broadband, with component carriers that are 100MHz wide vs. 20MHz for 4G LTE.  Thus, broadband operation in multiples of 100MHz is required by both mobile devices and base-stations.  5G is anticipated to operate at both mmW bands (28GHz and 39GHz) and Sub 6GHz (e.g. 3.5 GHz) and in the case of mmW extreme bandwidths of 800MHz are expected.

As shown in the table, NanoSemi’s Linearization technologies are expected to improve 5G performances for all bands of operation.

Wideband linearization benefits to 5G devices
Sub 6 GHz mmW
Wideband (>=100MHz) Wideband (800MHz)
Compensates low cost components Boosts GaAs/CMOS PA output power
Minimum Adaptation Minimum Adaptation
Improves power efficiency Improves power efficiency

LTE based mobile devices have traditionally used envelop tracking to improve the efficiency and output of amplifiers.  However, envelop tracking is challenged to meet the higher bandwidth and other critical characteristics of 5G waveforms as can be seen below.

Comparison of envelope tracking, traditional DPD based upon GMP and NanoSemi’s linearization based upon wide band signals (>80MHz)

For more details on how NanoSemi enables 5G, please see the white paper here.

Test Equipment

Test and Measurement Equipment

  • Improve test and measurement equipment’s native performance
  • A complete linearization test suite for design optimization

Test equipment needs the highest performance levels in order to be the golden reference for any digital device and Power Amplifier testing.  NanoSemi’s linearization improves the performance the digital chains for test equipment.  Indeed, our Linearization techniques are part of the standard offering many tier 1 Power Amplifier testing platforms in order to provide a golden linearization reference for testing, thereby establishing the benchmark for Power Amplifier and linearization performance.

NanoSemi provides a linearization testing suite through our partner test equipment manufacturers. The testing suite allows designers to verify power amplifier’s performance with NanoSemi’s state of the art linearizer designs and hence allows for rapid design optimization.