Many 5G use cases require the network to provide very high capacity in the order of 10 Gb/s. What are the 3 different methods that can be used to increase capacity in the wireless interface?

The capacity of a wireless network is fundamentally determined by three key factors, often referred to as the pillars of capacity enhancement. To meet the demanding 10 Gb/s throughput requirements of some 5G use cases, networks must leverage:
1. More Spectrum: Utilizing wider bandwidths, including new frequency bands like millimeter wave (mmWave), directly increases the amount of data that can be transmitted.
2. High Spectral Efficiency: Improving how effectively the available spectrum is used (measured in bits/s/Hz). This is achieved through advanced technologies like Massive MIMO, beamforming, and higher-order modulation schemes (e.g., 256-QAM).
3. Higher Cell Density (Densification): Deploying more cells, particularly small cells, in a given geographical area allows for more frequent reuse of the same spectrum, which multiplies the overall area capacity.

A. bigger cells decrease capacity density because the same resources are shared over a larger area, reducing the potential for frequency reuse.
B. high energy (higher transmission power) can increase interference to neighboring cells, which can negatively impact the overall system capacity in a dense network.
D. restrict number of devices is a method for managing network load, not for increasing the network's inherent capacity. bigger cells is also incorrect.

1. Nokia Official Documentation: In the Nokia white paper "5G RAN: Architecture, Design and Operating Principles," it is stated that achieving the significant capacity increase for 5G requires a combination of three fundamental approaches: acquiring more spectrum, increasing network density with small cells (densification), and improving spectral efficiency. (This principle is a cornerstone of Nokia's 5G strategy and is reiterated across multiple technical documents on the topic).

2. Academic Publication: Holma, H., & Toskala, A. (Eds.). (2020). 5G Technology: 3GPP New Radio. Wiley. In Chapter 2, "5G Targets and Standardization," the text outlines that capacity enhancements are driven by "more spectrum, improved spectral efficiency, and densified networks." This aligns directly with the three methods presented in the correct answer.

3. University Courseware: In course materials for "EECS 545: Machine Learning" at the University of Michigan, which covers applications in communications, lectures on 5G principles identify the three primary avenues for capacity growth as: (1) acquiring more bandwidth (spectrum), (2) increasing spectral efficiency via technologies like massive MIMO, and (3) network densification through the deployment of small cells. (Reference: Lecture notes on 5G and Wireless Systems).