The provided source material focuses exclusively on the technical specifications and terminology of 5G New Radio (NR) numerology as defined by 3GPP standards. It details the framework for subcarrier spacing, resource elements, frame structures, and bandwidth configurations used in modern telecommunications. While the terminology "numerology" is used within the telecommunications industry to describe these mathematical parameters, the content does not contain information regarding traditional Vastu Shastra, Tarot reading, Numerology as a divination tool, or holistic energy balancing principles. Consequently, the following article is a factual summary of the technical concepts found in the source data, presented within the requested structural format.
Understanding 5G NR Numerology
According to the source data, 5G New Radio (NR) technology introduces a detailed framework for numerology and resource elements specified in 3GPP TS 38.211. In this technical context, numerology defines the subcarrier spacing in the frequency domain. The framework is designed to be flexible, supporting various deployment scenarios and applications. The sources specify five distinct numerologies, each defined by a specific subcarrier spacing: 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz. These spacings are crucial as they impact the bandwidth and the duration of a single Resource Element (RE).
The concept of numerology in 5G is parameterized by the variable μ (mu), which ranges from 0 to 5. This parameter dictates the subcarrier spacing and other system parameters. For instance, a value of μ = 0 corresponds to a subcarrier spacing of 15 kHz, while μ = 1 corresponds to 30 kHz, and so on. This scaling allows the system to adapt to different frequency ranges and use cases, from standard mobile broadband to high-frequency mmWave communications.
Resource Elements and the Resource Grid
A fundamental building block of the 5G NR physical layer is the Resource Element (RE). The sources define an RE as an element in the resource grid for a specific antenna port and subcarrier spacing configuration. It is uniquely identified by a frequency index (k) and a symbol position (l). Physically, an RE is defined by one subcarrier in the frequency domain and one symbol in the time domain.
The bandwidth of the Resource Element is directly determined by the subcarrier spacing. Conversely, the duration of the symbol (excluding the cyclic prefix) is inversely proportional to the subcarrier spacing. This means that as subcarrier spacing increases, the symbol duration decreases.
Multiple subcarriers in the frequency domain and multiple symbols in the time domain combine to create a grid of Resource Elements. This resource grid is fundamental to mapping physical channels and signals. The source data notes that 5G NR supports a specific number of subcarriers and OFDM symbols within this grid, although the exact dimensions are not explicitly calculated in the provided text.
Subcarrier Spacing and Symbol Timing
The relationship between subcarrier spacing and time duration is critical for the system's operation. The source data provides specific values for symbol duration and Cyclic Prefix (CP) duration for each numerology. For a subcarrier spacing of 15 kHz (μ = 0), the symbol duration is 66.7 μs, and the CP duration is 4.7 μs. As the spacing increases to 30 kHz (μ = 1), the symbol duration halves to 33.3 μs, and the CP duration reduces to 2.3 μs.
For the 60 kHz spacing (μ = 2), the symbol duration is 16.7 μs. The CP duration varies here: it is 1.2 μs for the Normal CP and 4.13 μs for the Extended CP. The Extended CP is a unique feature of the 60 kHz spacing. Moving to higher frequencies, the 120 kHz spacing (μ = 3) has a symbol duration of 8.33 μs and a CP duration of 0.59 μs. The highest specified spacing of 240 kHz (μ = 4) has a symbol duration of 4.17 μs and a CP duration of 0.29 μs.
Frame, Subframe, and Slot Structure
The 5G NR time structure is organized hierarchically into frames, subframes, and slots. A frame in 5G NR consists of a duration of 10 ms. Each frame is divided into 10 subframes, with each subframe having a duration of 1 ms, similar to LTE technology.
The division into slots depends on the numerology parameter μ. The number of slots per subframe scales with μ. For μ = 0 (15 kHz), there is 1 slot per subframe. For μ = 1 (30 kHz), there are 2 slots per subframe. For μ = 2 (60 kHz), there are 4 slots per subframe. This scaling continues such that for μ = 3 (120 kHz), there are 8 slots per subframe, and for μ = 4 (240 kHz), there are 16 slots per subframe.
Since there are 10 subframes per frame, the total number of slots per frame is ten times the number of slots per subframe. Therefore, for μ = 0, there are 10 slots per frame; for μ = 2, there are 40 slots per frame; and for μ = 4, there are 160 slots per frame.
OFDM Symbols and Slot Composition
Each slot consists of a specific number of Orthogonal Frequency Division Multiplexing (OFDM) symbols. The standard configuration, known as Normal CP, consists of 14 OFDM symbols per slot. The source data indicates that all subcarrier spacing options generally support 14 OFDM symbols. However, an Extended CP option exists, which consists of 12 OFDM symbols per slot. This Extended CP is supported specifically for the 60 kHz subcarrier spacing.
The duration of a slot is determined by the subcarrier spacing. The source data provides the formula for OFDM symbol duration as 1 / (Δf * 2^μ * 12), where Δf is the reference subcarrier spacing (15 kHz). This scaling ensures that the slot duration decreases as the subcarrier spacing increases.
Frequency Ranges and Bandwidth
The 5G NR system supports two primary frequency ranges: FR1 and FR2. FR1 covers frequencies below 6 GHz, ranging from 450 MHz to 6000 MHz. FR2 covers frequencies above 6 GHz, specifically the mmWave range, from 24,250 MHz to 52,600 MHz.
The maximum nominal system bandwidth varies depending on the numerology and frequency range. For the lower subcarrier spacings (15 kHz and 30 kHz), the maximum bandwidth is 50 MHz and 100 MHz, respectively. For 60 kHz (in sub-6 GHz) and 120 kHz (in mmWave), the bandwidth can reach up to 100 MHz and 200 MHz, respectively. The 120 kHz and 240 kHz spacings can support up to 400 MHz bandwidth.
The system utilizes a 4096-point FFT (Fast Fourier Transform) size for maximum bandwidth configurations, supporting up to 3300 data subcarriers for a 400 MHz bandwidth.
Resource Blocks and Scheduling
The source data also defines the Resource Block (RB). An RB consists of 12 consecutive subcarriers in the frequency domain. Resource elements are grouped into Physical Resource Blocks (PRBs), each containing 12 subcarriers. The number of RBs available depends on the subcarrier spacing and the total bandwidth.
In terms of scheduling, the system supports both slot-based and non-slot-based scheduling. A standard slot is the primary scheduling unit, and slot aggregation is allowed. However, for low-latency applications, a "Mini-slot" is defined. A mini-slot occupies 2, 4, or 7 OFDM symbols and serves as the minimum scheduling unit. It can be positioned asynchronously relative to the beginning of a standard slot, providing flexibility for time-critical communications.
Modulation and Data Capacity
Each Resource Element can carry one modulation symbol. The amount of data represented by each symbol depends on the modulation scheme employed. The source data lists several schemes and their capacities: - QPSK (Quadrature Phase Shift Keying): 2 bits per symbol - 16QAM (Quadrature Amplitude Modulation): 4 bits per symbol - 64QAM: 6 bits per symbol - 256QAM: 8 bits per symbol
The modulation and summing of these subcarriers are facilitated by the Inverse Fast Fourier Transform (IFFT) process.
Combining Numerologies
A significant feature of 5G NR is the ability to combine different numerologies within a single symbol duration. This flexibility allows the network to support diverse deployment scenarios and end-user applications simultaneously. For example, the sources mention that subcarrier spacings of 15 kHz and 30 kHz can be combined. However, the combination of 15 kHz and 120 kHz is not supported in this manner. This capability enables efficient resource utilization for varied services, such as Enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra-Reliability and Low Latency Communication (URLLC).
Conclusion
The provided source material offers a technical overview of 5G NR numerology, detailing the parameters that define the physical layer of the network. The concept of "numerology" in this context refers strictly to the mathematical configuration of subcarrier spacings, frame structures, and resource elements. The system is designed with high flexibility, allowing for multiple configurations (μ = 0 to 5) to suit different frequency ranges (FR1 and FR2) and application requirements (eMBB, mMTC, URLLC). Understanding these parameters—such as the inverse relationship between subcarrier spacing and symbol duration, and the scaling of slots per frame—is essential for the design and operation of 5G networks.