# MAC Protocols for mmWave Communication: A Comparative Survey +
## 3 MAC Layer and Beamforming for mmWave  
### MAC Layer  
The 5G mmWave MAC layer will eventually be significantly redesigned to take advantage of the highly directed, ultra-low latency end-to-end service demands, as well as 20 times higher peak speeds than 4G [4; 15; 23; 24; 25; 26; 27; 28]. In the ultra-dense mmWave networks, variations in traffic can occur faster than routes can be adjusted. Therefore, resource assignments inside a MAC layer must work in a faster time frame and be reactive to the immediately offered load. A routing layer assists the MAC layer for this purpose by providing link-specific information that classifies dedicated, restricted, and shared resources [29]. Moreover, MAC layers can be modified to support high streaming and \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Ref.** & **Year** & **Title** & **Scope** \\ \hline
[13] & 2015 & A Survey of Millimeter Wave Communications (mmWave) for 5G: Opportunities and Challenges & Interference management, spatial reuse, anti-blockage, and mobility dynamics for 60 GHz band \\ \hline
[2] & 2015 & A Survey of 5G Network: Architecture and Emerging Technologies & Distributed spectrum sharing and management, interference management, joint scheduling, and the procedure of various interference management in 5G based MIMO \\ \hline
[10] & 2015 & Millimeter Wave Cellular Networks: A MAC Layer Perspective & Scheduling, association, random access, synchronization, and interference management \\ \hline
[14] & 2016 & Next Generation 5G Wireless Networks: A Comprehensive Survey & Directional MAC protocols and their multiplexing techniques, mmWave based physical layer aspect \\ \hline
[15] & 2016 & Design Aspects of Short-range Millimeter-wave Networks: A MAC Layer Perspective & Short-range mmWave collision-aware hybrid resource allocation and multi-hop connectivity issues \\ \hline
[16] & 2016 & Millimeter-Wave (mmWave) Medium Access Control: A Survey & Directional mmWave beam management, relaying, and scheduling \\ \hline
[17] & 2018 & IEEE 802.11 ay-Based mmWave WLANs: Design Challenges and Solutions & MAC issues for the 802.11 ay, channel allocation, spatial sharing, and interference management \\ \hline
[18] & 2018 & Millimeter Wave Communication: A Comprehensive Survey & MAC protocols and scheduling systems for ad hoc networks, mesh networks, and wireless personal area networks (WPANs) \\ \hline
[19] & 2019 & On Medium Access Control Schemes for Wireless Networks in the Millimeter-wave and Terahertz Bands & Deafness issues, control channel selection mechanisms, blockage issues, mobility management, and spatial reuse strategies \\ \hline
[20] & 2020 & Survey on Wireless Networks Co-existence: Resource Sharing in the 5G Era & Resource sharing and access layer solutions \\ \hline
[21] & 2020 & A Comprehensive Survey on Millimeter Wave Communications for Fifth-Generation Wireless Networks: Feasibility and Challenges & Initial access, multi-hop overhead issues, mobility management, and handover \\ \hline Our survey & MAC Protocols for mmWave Communication: A Comparative Survey & Resource allocation, interference management, anti-blockage, deafness issues, scheduling, random access and synchronization, multi-hop connectivity, and individual protocol review \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative analysis of the existing surveys. downloading services in the ultra-dense mmWave networks and mmWave WPANs, which are considered to be the foundation of future generation communication systems. However, there are several problems that need to be considered when providing mmWave services using the existing MAC protocols. Mobility management and initial access are some examples. These functions define how a user equipment (UE) connects and maintains its connection to the connected network. However, UEs must decode a shared directed channel so that they can retrieve system information in a mmWave cellular network.