Signal analyzer 5G NR

5G NR (New Radio) is the fifth-generation radio access technology developed by the 3rd Generation Partnership Project (3GPP) for 5G mobile communication networks. It is designed to provide higher data rates, lower latency, increased network capacity, and improved energy efficiency compared to previous generations, such as LTE.

5G NR uses Orthogonal Frequency-Division Multiplexing (OFDM), which divides the available spectrum into multiple orthogonal subcarriers. This enables flexible resource allocation and efficient transmission of data to multiple users. Unlike LTE, which primarily uses fixed subcarrier spacing, 5G NR introduces a flexible numerology. The subcarrier spacing can be adjusted according to the operating frequency, deployment scenario, and service requirements.

5G NR covers FR1 and/or FR2 frequency range. FR1 is the lower frequency range, commonly referred to as Sub-6 GHz, because it primarily covers frequencies below 6 GHz. FR1 is widely used for commercial 5G deployments.

Note: HackRF supports only FR1 frequency range.

Typical bandwidths of 5G NR channel in FR1 are from 5 to 100 MHz.

Note: HackRF supports only 20 MHz bandwidth. Wider bandwidths can be analyzed, if 20 MHz selection covers at least one Synchronization Signal Block of the whole channel bandwidth.

5G NR analyzer searches for NR synchronization blocks, decodes PBCH/MIB and SIB1 when available, and estimates recent downlink air load.

Cell table columns

• PCI - NR Physical Cell ID.
• PLMN - Public Land Mobile Network.
• TAC - Tracking Area Code.
• NCI - NR Cell Identity.
• BW - nominal channel bandwidth decoded from SIB1.
• Band - NR operating band, shown as n-band.
• Air load - occupied-PRB estimate in the captured bandwidth.
• SSB - detected Synchronization Signal Block frequency.
• iSSB - decoded SSB index.
• PSS / SSS - synchronization signal quality.
• DM-RS - PBCH demodulation reference-signal quality.
• CFO - carrier frequency offset.
• MIB - Master Information Block status.
• SIB1 - System Information Block 1 status.

Decode breadcrumb

• PBCH - Physical Broadcast Channel.
• MIB - Master Information Block.
• CORESET - Control Resource Set.
• CSS - Common Search Space.
• PDCCH - Physical Downlink Control Channel.
• SI-RNTI - System Information Radio Network Temporary Identifier.
• DCI - Downlink Control Information.
• PDSCH - Physical Downlink Shared Channel.
• LDPC - Low-Density Parity-Check channel coding.
• TBS - Transport Block Size.
• AL - aggregation level.
• nCCE - control-channel element index.
• MCS - Modulation and Coding Scheme.
• RV - Redundancy Version.

System details

• Physical Cell ID - NR physical-layer cell identity.
• PLMN - public mobile network identifier.
• Tracking Area Code - mobility and paging area.
• NR Cell Identity - 36-bit cell identity from SIB1.
• NR band - operating band advertised by SIB1.
• SSB frequency - measured center of the detected synchronization block.

Radio details

• PSS / SSS quality - synchronization quality for this PCI.
• PBCH DM-RS quality - reference-signal confirmation of the PCI.
• Frequency offset - estimated residual tuning error.
• SSB index - decoded SSB index for the capture.
• System frame number - radio-frame timing decoded from MIB.
• Common SCS - common subcarrier spacing signalled by MIB.
• kSSB - SSB subcarrier offset.
• DM-RS type-A position - PDSCH DM-RS start position.
• CORESET0 / SearchSpace0 - initial common control-channel configuration.
• Cell access - whether MIB permits ordinary access.
• Carrier resource grid - downlink carrier bandwidth and subcarrier spacing from SIB1.

SIB1 details

• Initial downlink BWP - common downlink Bandwidth Part.
• Offset to Point A - common resource-block grid offset.
• SI window - time window in which scheduled System Information is transmitted.
• SI schedule - SIB mapping, repetition period and broadcast status.
• Other-SI search space - common search space used for other System Information.
• BCCH modification coefficient - multiplier used for BCCH modification periods.
• Paging cycle - default idle-mode paging cycle.
• Paging frame offset - paging frame configuration.
• Paging occasions per frame - number of paging occasions in a paging frame.
• Paging search space - common search space monitored for paging.

Air load

Air load is a radio-resource occupancy estimate for the captured NR downlink span. With 10 MS/s input, the measurement does not cover resources outside the observed bandwidth. It is not BTS CPU load, backhaul load, user count or guaranteed throughput.