# 5G 101 Part 2
## 5G SPECTRUM
**DEF:** range of radio frequencies in the sub-6 GHz range and the millimeter-wave frequency range that is 24.25 GHz and above. The 5G spectrum refers to the radio frequencies that carry data from user equipment (UE) to cellular base stations to the data's endpoint.-(*https://bit.ly/2KtKfPz*)
> source: https://bit.ly/2RZbcyT
### 5G SPECTRUM CHALLENGES
- Interference because wireless signal propagation depends on factors such as the weather and the natural environment
- Government granting spectrum license to mobile network operators.
- World communication organization management of spectrum distribution

**NOTE: "In 5G networks, the size of cell differs in spectrum range. The lower the frequency range the larger/macro cells is needed and the higher frequency range requires smaller cells"**

## 5G NEW GENERATION (NEW RADIO)
- A new 5G-specific radio communication system called New Radio (NR) has been defined with no backward compatibility with the existing LTE and LTE-Advanced systems.
- Full Architecture of NR
- Consists of **gNBs** and **eNBs**, providing the user plane and control plane protocol terminations towards the UE. The gNBs are interconnected with each other by means of the **Xn** interface. The **gNBs** are also connected by means of the N interfaces to the 5GC, more specifically to the **AMF(Access and Mobility Management Function)** by means of the **N2** interface and to the **UPF(User Plane Function)** by means of the **N3** interface.
- ***Functions***
- 
- **NR supports**
- *Scalable OFDM based air interface*-Address diverse services,spectrum, deployments
- 
- **5G NUMEROLOGY** - refers to the configuration of waveform parameters, and different numerologies are considered as OFDM-based sub-frames having different parameters such as subcarrier spacing/symbol time, CP size, etc. -*3GPP 5G standardization contributions*
-  *Slots are defined as 14 OFDM Symbols and their time interval depends on subcarrier spacing*
- *Flexible slot-based framework*- Low latency, URLLC,forward compatibility
- Scalable slot duration, mini-slot and slot aggregation
- Self-contained slot structure
- Traffic pre-emption for URLLC
- Support for different numerologies for different services
- **NR transmission is well-contained in time and frequency**
- *Advanced channel coding* - Support large data blocks, reliable control channel
- **Bandwith Part (BWP)** - enable more flexibility in how resources are assigned in a given carrier.
- provide flexibility so that multiple, different signal types can be sent in a given bandwidth.
- enable multiplexing of different signals and signal types for better utilization and adaptation of spectrum and UE(User Equipment) power.
- can be configured differently with its own signal characteristic, enabling more efficient use of the spectrum and more efficient use of power.
- good for integrating signals with different requirements.
- One BWP may have reduced energy requirements, while another may support different functions or services, and yet another may provide coexistence with other systems.
- *Massive MIMO* - Large # of antennas to increase coverage/capacity
- **KEY FEATURES**
- In each type of location/places, differs on its needs especially on capacity. Dense Urban requires more carrying capacity compared to Mid band Metro and lowband nationwide.
- Multi-beam operation. The more congested the area is, the narrow the beams it should be.
- **lower frequencies**, a single beam can be used to provide wide coverage
- **higher frequencies**, multiple beams can be used to extend coverage
- Enhance channel status information
- Enhance reference signals, transmission schemes, etc
- **CHALLENGES**
- The antennas will be heavier, meaning that the existing poles may not be able to bear the load.
- can work for some sites but may not be economical for all sites
- Power upgrade would be required too as the new active antennas would consume more power
- ince each site serves multiple sectors and frequencies, it is quite possible that backhaul upgrades would be necessary as well.
- Existing backhaul may not be able to cope with massive increase in data traffic.
- *Mobile mmWave* - For extreme capacity and throughput
- **Overcoming Challenges in mmWave** - *https://bit.ly/3eGOZPP*
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### More on 5G

###### tags: emergingtechnologies