OFDM/OFDMA Advanced

OFDM / OFDMA Advanced training course

OFDM / OFDMA Advanced training course describes all aspects of the operation of radio interfaces based upon OFDM and OFDMA technology.

The OFDM / OFDMA course commences by detailing the radio signal propagation phenomena present over transmission paths.

Having covered these basics, the OFDM / OFDMA Advanced training looks in depth at the operation for OFDM and OFDMA. The major advantages of OFDM / OFDMA are explained along with the ways available to use them effectively. These include topics such as algorithms for adaptive subcarrier assignment, modulation, power control, etc..

The next phase of the OFDM / OFDMA training course looks at two key families of DSP algorithms: methods for synchronization; and channel estimation and correction. Next, methods of incorporating OFDM / OFDMA-based radio interface into wireless access network is detailed with particular focus on methods to control co-channel interference.

The course then moves on to detail how OFDM / OFDMA can be combined with multiple antennas systems.

The training course finishes by looking at a comparison of various contemporary OFDM / OFDMA systems.

This OFDM / OFDMA Advanced training course is developed for telecom professionals working with hardware and software development, implementation, system engineering, testing and verification, as well as product and project management.

OFDM / OFDMA Advanced training course contents

Digital Communications Introduction

• Review of single-carrier digital modulation and mapping schemes

• Review of TDMA and FDMA multiple access schemes

• Spread spectrum transmission and CDMA

• General model of a digital communications system

Radio Signal Propagation Basics

• Multipath channels

• Time, frequency and space diversity

• Large-scale and small-scale propagation effects

• Path losses, shadowing, Rayleigh, Rician fading

• Inter-symbol interference and possible countermeasures

Principles of OFDM

• Serial vs. parallel multicarrier transmission

• Block model of an OFDM modem including transmitter and receiver

• IFFT/FFT functionality and practical implementation

• Determination of the key OFDM parameters

• Structure of the OFDM symbol

• Sub-carrier orthogonality and spacing; OFDM signal spectrum

• Cyclic Prefix (CP), linear and circular convolution, impact on equalization

• Peak-to-average power ratio of RF signal – its affects and solution

• Time-domain and frequency-domain OFDM signal representation

OFDMA Principles

• OFDMA as a scheme extending OFDM

• Multi-user diversity benefits

• Adaptive subcarrier allocation; adaptive allocation of time and frequency resources

• Adaptive modulation and coding for OFDMA systems

• Example scheduling approaches and MAC protocols

• Single-carrier FDMA

• Summary of adavantages and disadvantages of OFDMA

OFDM/OFDMA Synchronization

• Classification and characterization of synchronization offsets: Carrier Frequency Offset (CFO), Carrier Phase Offset (CPO), symbol timing offset and sampling clock offset

• Time-domain or frequency-domain estimation and correction of synchronization offsets

• Review of symbol timing synchronization methods including algorithms based on CP

• Review of carrier frequency synchronization methods including algorithms based on pilots

• Sampling rate synchronization methods

OFDM/OFDMA Channel Estimation and Correction

• Review of pilot types and preambles (block, comb, mixed, grid)

• Requirements for minimal pilot separation in the time and in the frequency domain

• Structure of OFDM/OFDMA channel estimator and corrector

• Basic channel correction schemes: zero-forcing and MMSE equalizer

Use of Multiple Antennas in OFDM/OFDMA

• Fundamentals of multiple-antennas

• Review of multiple-antenna methods, including: transmit diversity, spatial multiplexing, single-user and multi-user MIMO, beamforming

• MIMO schemes without feedback (open-loop) and with feedback (closed-loop)

• Combination of MIMO and OFDM/OFDMA

• Scheduling of 3-dimensional resource grid (time, frequency and space)

• Channel estimation and pilots for MIMO/OFDM/OFDMA

• Methods combining STBC and OFDM

• Methods combining SFBC and OFDM

• Methods combining Spatial Multiplexing and Beamforming with OFDM

Cellular OFDMA

• Review of co-channel interference management schemes

• Interference randomization, avoidance, cancellation and coordination

• Single Frequency Network (SFN) concept in OFDM/OFDMA-based systems

Full reuse of one

• Integer and fractional frequency reuse

• Co-channel interfaces comparison between FDD and TDD

Review of Contemporary Systems Applying OFDM/OFDMA

• 3GPP-LTE Rel 8 and 9

• 3GPP-LTE Rel 10 (LTE Advanced)

• WiMAX (IEEE 802.16d and 802.16e)

• Wi-FI

• Broadcasting (DAB, DVB)

Pre-requisites:

In order to gain the most from the OFDM / OFDMA Advanced training course it is recommended that attendees have a general knowledge about the architecture, terminology and modes of operation of the GSM/UMTS Radio Access Network. A general knowledge of broadband access systems (such as WiMAX, 3GPP-LTE), radio propagation and signal processing is also useful.

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