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Beyond Data: What role does the physical layer play in wireless communications?
In the seven-layer OSI model of computer networks, the physical layer, that is, the first layer, is most closely related to the actual connection between devices.The physical layer provides an electrical, mechanical and program interface for the transmission of media.This includes specifications for the shape and characteristics of the electrical connector, transmission frequency, line encoding used, and other low-level parameters.With the development of mobile computing, the *-PHY series interconnection agreement of MIPI Alliance is widely used in the market.
The physical layer defines how the original bit stream is transmitted between network nodes through physical data links.
The role of the physical layer cannot be underestimated.It is the basis of many high-level functions, implements support for different hardware technologies, and is able to translate between logical communication requests and hardware-specific operations.For example, through the Open System Interconnection (OSI) architecture, the physical layer is not limited to the transmission of electrical signals, but also includes data exchange through various transmission media.
Main services of the physical layer
Some of the main functions performed by the physical layer include: bit-by-bit or symbol-by-symbol transmission of raw data, providing a unified transmission interface, including mechanical specifications for electrical connectors and cables.For example, it sets electrical standards such as maximum cable length, transmission line signal strength, and impedance.In addition, the physical layer also needs to consider electromagnetic compatibility, which means that the electromagnetic spectrum and signal strength must be planned reasonably to reduce interference during communication.
Management of data streams includes synchronous bit synchronization in serial communication, or start-stop signal and flow control in asynchronous serial communication.
In terms of sharing transmission media, the physical layer can use simple circuit switching or multiplexing techniques to manage conflicts and interference.For multiple Ethernet interfaces, protocols such as CSMA/CD provide more complex media access control solutions.
Sublayers of physical layer and their related technologies
The signal sublayer in the physical layer is dedicated to interface with the Media Access Control (MAC) sublayer of the data link layer and performs functions such as symbol encoding, transmission and reception.This paragraph is crucial to ensure the correct transmission and connection of data.Of course, with the advancement of technology, more and more applications are integrating physical layer design into existing systems, such as wireless local area network (Wi-Fi), 3G/4G/5G communication and USB protocols.
Risks are no longer limited to wired and wireless systems, and many new physical layer agreements such as M-PHY are also beginning to be widely used.
The physical transceiver (PHY) part of Ethernet operates in the physical layer of the OSI network model, focusing on implementing physical connections to Ethernet.Its design is to provide physical access to the analytical signal with the transmission medium and communicate with the media independent interface (MII) interface to better carry out data transmission.
Future Outlook
With the continuous popularity of the Internet of Things and smart devices, the role of the physical layer is becoming more and more important.One of the challenges designers needs to face is how to maintain communication quality and efficiency in a wide range of transmission technologies.More and more systems are moving towards a highly integrated direction, integrating physical layer functions with high-level logic.
In future wireless communications, can the physical layer adapt to changing needs and technological advancements?
