5G Network Deployment

The millimeter wave and Massive MIMO work together in a successful 5G network deployment. While higher frequencies require greater antenna volume, they also allow for a much smaller antenna form factor, due to their shorter wavelength. Deploying and correctly aligning these complex antenna arrays can present challenges. 

5G antenna integrators, working at the top of the cell tower, validate the antenna array configuration against the RF planning tool specifications. Failing to complete this validation properly can lead to coverage gaps and service degradation. This is sometimes misinterpreted as an insufficient level of cell site infrastructure, which is an expensive misdiagnosis.

High confidence in 5G antenna deployment is achieved through reliable antenna alignment solutions. The VIAVI 3Z RF Vision Antenna Alignment Tool detects obstructions in the antenna transmission path and verifies correct roll, tilt, and azimuth settings. A built-in camera and augmented reality features can be used to generate automated line of sight surveys and detect unforeseen obstacles in the antenna’s path.

In addition to high frequency operation, the 5G air interface introduces a greater degree of spectrum sharing. Flexible sub-carrier spacing and numerology options are elements of the 5G air interface, along with dynamic time division duplex (TDD). This method uses a single frequency for both uplink and downlink transmission, divided into separate time slots. TDD is similar to traffic control methods that open or close lanes in each direction, based on rush hour demand. Using TDD, uplink and downlink traffic can be intelligently balanced to reduce system latency. 

5G air interface innovations can also lead to additional deployment and test challenges. Traditional test practices like gated sweep routines are intended to assess only a single direction of traffic. More visibility is needed to distinguish real signals from interference, especially when TDD has been employed. Innovative VIAVI real-time spectrum analyzers utilize advanced 5G-friendly options. This includes the persistence spectrum and spectrogram features that provide a more detailed view of the monitored frequency band.

The effective combination of massive MIMO, beamforming, and spatial multiplexing allows the 5G coverage to be enhanced. Unique to 5G network deployment, the beamforming technique can be used to focus wireless signals toward a specific receiving device. Combining multiple signals constructively improves bandwidth and coverage. The proper application of beam forming is essential for 5G coverage, particularly in the FR2 band (24.25 – 52.6 GHz). Beamforming also introduces unique challenges for monitoring, maintenance, and validation.

Constructive interference is the scientific principle used improve 5G coverage in the FR2 band by strategically layering signals from each small array. When beam forming infrastructure is deployed, the phase and amplitude of each antenna is optimized to produce a much higher gain directional overall. The 3GPP standards provide flexibility with respect to beam forming policies and SSB location. This lack of standardization can also create to challenges for defining 5G beam forming test practices. 

Get the prescription for precise SSB configuration in the VIAVI 5G Beamforming Profile Rx blog post.

Millimeter wave is defined as the spectrum between 30GHz and 300GHz. The low-band spectrum resides below 1GHz. Between these two extremes are the mid-bands, located between 1GHz - 2.6GHz and 3.5GHz - 6GHz. Despite the emphasis on 5G millimeter wave, low and mid-band spectrums are also important to 5G capacity and reliability. The high frequency millimeter wave is prone to distortion and limited in range. With a broad spectrum of frequencies available, this can be addressed through DSS and adaptive beam switching. For example, a UE can be transferred to a more stable, lower frequency as needed until a stable high-frequency connection is established. 

The long range and immunity to signal distortion of the low-band spectrum have provided a sturdy foundation for generations of wireless infrastructure. Since low frequency also means slower speeds and higher latency, low-band has found less utility in the age of 5G. 

Some have described the 5G mid-band spectrum as the “Goldilocks” spectrum, with a just right compromise between the speed of millimeter wave and the signal integrity and range of low-band frequencies. This is especially true for the C-band frequency range, between 3.7 and 3.98 GHz.

So appealing is the mid-band spectrum for 5G that many operators are “refarming” 3G bands for 5G. In addition, 280 MHz of C-band spectrum was auctioned to the private sector by the FCC in 2020. These transitions help to alleviate the deficit in available mid-band spectrum needed for sustainable 5G deployment. 

The millimeter wave and Massive MIMO work together in a successful 5G network deployment. While higher frequencies require greater antenna volume, they also allow for a much smaller antenna form factor, due to their shorter wavelength. Deploying and correctly aligning these complex antenna arrays can present challenges. 

5G antenna integrators, working at the top of the cell tower, validate the antenna array configuration against the RF planning tool specifications. Failing to complete this validation properly can lead to coverage gaps and service degradation. This is sometimes misinterpreted as an insufficient level of cell site infrastructure, which is an expensive misdiagnosis.

High confidence in 5G antenna deployment is achieved through reliable antenna alignment solutions. The VIAVI 3Z RF Vision Antenna Alignment Tool detects obstructions in the antenna transmission path and verifies correct roll, tilt, and azimuth settings. A built-in camera and augmented reality features can be used to generate automated line of sight surveys and detect unforeseen obstacles in the antenna’s path.

In addition to high frequency operation, the 5G air interface introduces a greater degree of spectrum sharing. Flexible sub-carrier spacing and numerology options are elements of the 5G air interface, along with dynamic time division duplex (TDD). This method uses a single frequency for both uplink and downlink transmission, divided into separate time slots. TDD is similar to traffic control methods that open or close lanes in each direction, based on rush hour demand. Using TDD, uplink and downlink traffic can be intelligently balanced to reduce system latency. 

5G air interface innovations can also lead to additional deployment and test challenges. Traditional test practices like gated sweep routines are intended to assess only a single direction of traffic. More visibility is needed to distinguish real signals from interference, especially when TDD has been employed. Innovative VIAVI real-time spectrum analyzers utilize advanced 5G-friendly options. This includes the persistence spectrum and spectrogram features that provide a more detailed view of the monitored frequency band.

The effective combination of massive MIMO, beamforming, and spatial multiplexing allows the 5G coverage to be enhanced. Unique to 5G network deployment, the beamforming technique can be used to focus wireless signals toward a specific receiving device. Combining multiple signals constructively improves bandwidth and coverage. The proper application of beam forming is essential for 5G coverage, particularly in the FR2 band (24.25 – 52.6 GHz). Beamforming also introduces unique challenges for monitoring, maintenance, and validation.

Constructive interference is the scientific principle used improve 5G coverage in the FR2 band by strategically layering signals from each small array. When beam forming infrastructure is deployed, the phase and amplitude of each antenna is optimized to produce a much higher gain directional overall. The 3GPP standards provide flexibility with respect to beam forming policies and SSB location. This lack of standardization can also create to challenges for defining 5G beam forming test practices. 

Get the prescription for precise SSB configuration in the VIAVI 5G Beamforming Profile Rx blog post.

Millimeter wave is defined as the spectrum between 30GHz and 300GHz. The low-band spectrum resides below 1GHz. Between these two extremes are the mid-bands, located between 1GHz - 2.6GHz and 3.5GHz - 6GHz. Despite the emphasis on 5G millimeter wave, low and mid-band spectrums are also important to 5G capacity and reliability. The high frequency millimeter wave is prone to distortion and limited in range. With a broad spectrum of frequencies available, this can be addressed through DSS and adaptive beam switching. For example, a UE can be transferred to a more stable, lower frequency as needed until a stable high-frequency connection is established. 

The long range and immunity to signal distortion of the low-band spectrum have provided a sturdy foundation for generations of wireless infrastructure. Since low frequency also means slower speeds and higher latency, low-band has found less utility in the age of 5G. 

Some have described the 5G mid-band spectrum as the “Goldilocks” spectrum, with a just right compromise between the speed of millimeter wave and the signal integrity and range of low-band frequencies. This is especially true for the C-band frequency range, between 3.7 and 3.98 GHz.

So appealing is the mid-band spectrum for 5G that many operators are “refarming” 3G bands for 5G. In addition, 280 MHz of C-band spectrum was auctioned to the private sector by the FCC in 2020. These transitions help to alleviate the deficit in available mid-band spectrum needed for sustainable 5G deployment.