Search results
Modulation and Demodulation. Introduction. A communication system that sends information between two locations consists of a transmitter, channel, and receiver as illustrated in Figure 1. The channel refers to the physical medium carrying the information signal (voice, video, data etc.) from one location to another.
• Probability is the core mathematical tool for communication theory. • The stochastic model is widely used in the study of communication systems. • Consider a radio communication system where the received signal is a random process in nature: – Message is random. No randomness, no information. – Interference is random.
- 5MB
- 298
COMPACT LECTURE NOTES on ADVANCED COMMUNICATION THEORY. Prof. Athanassios Manikas, Autumn 2004. Principles of Spread Spectrum Systems. Outline: ì Basic concepts, models and classification and modelling of jammers. ì Principles of PN-Sequences: The significance of auto-correlation for code tracking and for suppressing multipath and ISI.
- Signal Retrieval and Communication
- Major Events
- Block Diagram of a Communication System
- Components of Block Diagram
- Channel Characteristics
- Characteristics
- Traffic offloading
- Spectrum extension
- Major Issues
- Characteristics
- Systems Analysis Techniques
- Probabilistic Approaches to System Optimization
Theory of systems for the conveyance of information Characteristics of communication systems Uncertainty Noise and “information” (deterministic vs probabilistic) Keep in mind: Signal retrieval problem Communication (only particular type of signal retrieval problem) Usually two resources to consider Bandwidth vs. Power
Innovations in microelectronics, signal processing, information theory have led to the proliferation of communication systems Major Events Major Events Which OSI Layer Will We Focus On?
Keep in mind that this is only a model! Can we make it simpler? More complicated? Consequences?
Input transducer Messages Analog or digital Message conversion E.g. speech voltage variations Transmitter Couple the message to the channel Modulation, filtering, amplification, and coupling Modulation For the ease of radiation To reduce noise and interference For channel assignment For multiplexing or transmission of several messages over a sing...
Channel Signal degradation (convolutive noise) Additive “noise” Sensor noise, thermal noise, interference (e.g. MUI, jammer, ...) Receiver Demodulation, amplification Output transducer Loudspeaker, tape recorder, PCs, CRT, LCD, etc. Channel Characteristics Additive noise sources (usu. less troublesome) Internal noise Noise generated by components w...
Large frequency reuse factor Performance enhanced by increasing spectrum efficiency
(alternative means for communications) WiFi offload, D2D, etc. Dense urban Shopping mall Non-orthogonal multiple access controller Massive MIMO, advanced receiver Multiple access technologies with Tx-Rx cooperative interference cancellation Current capacity
Existing cellular bands Home/office Cellular network assists local area radio access New cellular concept for cost/energy efficient dense deployment Very wide Super wide Hybrid access using coverage and capacity spectrum bands frequency
Effective backhaul design Mitigating relay to macrocell interference
Wired backhaul User-deployed Closed/open/hybrid access
Time and frequency domain analyses Looking at things from different perspective Modulation and communication theories Modulation theory employs time and frequency domain analyses to analyze and design systems for modulating and demodulating of information-bearing signals Analysis of interfering signals on system performance, and design of systems t...
As seen earlier, proper modeling of (additive and convolutive) noise (incl. interference) is important Probabilistic models are often used Why? Design Optimal design is crucial Many “optimal” design are not optimal – depends on perspective How do we do it? (We are engineers, this is important!) Statistical signal detection and estimation theory Wi...
- 2MB
- 21
Oct 31, 2023 · This article aims to provide a concise yet thorough exploration of modulation, focusing on modulation techniques, subcarriers, and constellation points. The conceptual framework aims to identify...
Modulation is a technique that changes the characteristics of the carrier frequency in accordance with the input signal. Figure 1.1 shows the conceptual block diagram of a modern wireless communication system, where the modulation block is shown in the inset of the dotted block. As shown in the figure, modulation is performed at the
People also ask
What is modulation theory?
Why do we need a comprehensive understanding of modulation techniques?
What is modulation in a communication channel?
Why is modulation important in Communication Technology?
Where is modulation performed in a radio communication system?
Which modulation techniques are used in telephony & internet connectivity?
Showcasing the essential principles behind modern communication systems, this accessi- ble undergraduate textbook provides a solid introduction to the foundations of communi- cation theory.
