QUADRATURE PHASE SHIFT TV

The radio interface was formerly named High Speed OFDM Packet Access (HSOPA), now named Evolved UMTS Terrestrial Radio Access (E-UTRA) The downlink of the 3GPP Long Term Evolution (LTE) fourth generation mobile broadband standard.The mobile broadband wireless access (MBWA) standard IEEE 802.20.The mobility mode of the wireless MAN/ broadband wireless access (BWA) standard IEEE 802.16e (or Mobile- WiMAX).The OFDM-based multiple access technology OFDMA is also used in several 4G and pre-4G cellular networks, mobile broadband standards, the next generation WLAN and the wired portion of Hybrid fiber-coaxial networks: The wireless personal area network (PAN) ultra-wideband (UWB) IEEE 802.15.3a implementation suggested by WiMedia Alliance.

QUADRATURE PHASE SHIFT TV

The terrestrial mobile TV systems DVB-H, T-DMB, ISDB-T and MediaFLO forward link.

The terrestrial digital TV systems DVB-T and ISDB-T.

The digital radio systems DAB/EUREKA 147, DAB+, Digital Radio Mondiale, HD Radio, T-DMB and ISDB-TSB.

The wireless LAN (WLAN) radio interfaces IEEE 802.11a, g, n, ac, ah and HIPERLAN/2.

Multimedia over Coax Alliance (MoCA) home networking.

ITU-T G.hn, a standard which provides high-speed local area networking of existing home wiring (power lines, phone lines and coaxial cables).

DVB-C2, an enhanced version of the DVB-C digital cable TV standard.

ADSL and VDSL broadband access via POTS copper wiring.

Wired version mostly known as Discrete Multi-tone Transmission (DMT) For further details, see the Usage section at the end of the article. The following list is a summary of existing OFDM-based standards and products. In practice, OFDM has become used in combination with such coding and interleaving, so that the terms COFDM and OFDM co-apply to common applications. COFDM was introduced by Alard in 1986 for Digital Audio Broadcasting for Eureka Project 147. This is done to overcome errors in mobile communication channels affected by multipath propagation and Doppler effects. In coded orthogonal frequency-division multiplexing ( COFDM), forward error correction (convolutional coding) and time/frequency interleaving are applied to the signal being transmitted. This mechanism also facilitates the design of single frequency networks (SFNs) where several adjacent transmitters send the same signal simultaneously at the same frequency, as the signals from multiple distant transmitters may be re-combined constructively, sparing interference of a traditional single-carrier system. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate intersymbol interference (ISI) and use echoes and time-spreading (in analog television visible as ghosting and blurring, respectively) to achieve a diversity gain, i.e.

Channel equalization is simplified because OFDM may be viewed as using many slowly modulated narrowband signals rather than one rapidly modulated wideband signal. The main advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions (for example, attenuation of high frequencies in a long copper wire, narrowband interference and frequency-selective fading due to multipath) without the need for complex equalization filters. Consecutive raised-cosine impulses, demonstrating zero- ISI property these closely resemble OFDM power spectrum (frequency domain). This maintains total data rates similar to conventional single-carrier modulation schemes in the same bandwidth. Each subcarrier (signal) is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate. OFDM was improved by Weinstein and Ebert in 1971 with the introduction of a guard interval, providing better orthogonality in transmission channels affected by multipath propagation. Demodulation is based on fast Fourier transform algorithms. Multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted, with each carrier modulated with bits from the incoming stream so multiple bits are being transmitted in parallel. In OFDM, the incoming bitstream representing the data to be sent is divided into multiple streams. OFDM is a frequency-division multiplexing (FDM) scheme that was introduced by Robert W. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/ 5G mobile communications. In telecommunications, orthogonal frequency-division multiplexing ( OFDM) is a type of digital transmission used in digital modulation for encoding digital (binary) data on multiple carrier frequencies.

Quadrature phase shift