Gi-Hong Im

51.84 Mb/s 16-CAP ATM LAN standard

The paper describes the characteristics and performance of the 16-CAP transmission scheme that has been chosen by the Technical Committee of the ATM Forum as the ATM LAN physical layer interface standard at 51.84 Mb/s for category 3 unshielded-twisted-pair (UTP) wiring. The two most attractive features of the 16-CAP transceiver are its capability of operating in the presence of multiple users in a voice-grade UTP cable and the straightforward way in which it can provide scalability to lower speeds. It is also shown in the paper how the carrierless AM/PM (CAP) modulation scheme used for the ATM LAN standard can be utilized to provide substantially higher data rates than 51 Mb/s when there is only one user in a cable. Under this condition, data rates up to 155 Mb/s can be achieved over category 3 wiring and significantly higher rates can be achieved over high-performance category 5 wiring. >

Bandwidth-efficient digital transmission over unshielded twisted-pair wiring

Describes techniques for achieving data rates up to 155 Mb/s over unshielded twisted-pair (UTP) wiring for local area network (LAN) applications in premises distribution systems. Duplex operation at these high data rates is achieved over two pairs of UTP wiring and with a bandwidth utilization that is less than 30 MHz, thus avoiding potential problems with radiation limits. The transmission scheme used for these LAN applications is carrierless AM/PM (CAP), which is a bandwidth-efficient two-dimensional passband encoding scheme. The paper also discusses in some detail a technique called NEXT equalization, which allows several users to share the same cable

Bandwidth-efficient digital transmission up to 155 Mb/s over unshielded twisted pair wiring

Techniques for achieving data rates up to 155 Mb/s over unshielded twisted pair wiring in premises distribution systems are described. These high data rates represent an improvement of about an order of magnitude in speed when compared to presently available data rates for local area networks operating over this communication medium. The transmission scheme proposed for achieving these higher data rates is carrierless AM/PM (CAP), which is a bandwidth-efficient two-dimensional passband line code. It is shown that a 32-CAP line code can be used to provide the fiber distributed data interface (FDDI) rate of 125 Mb/s over 100 m of voicegrade unshielded twisted pair (UTP) wiring in a channel bandwidth of 30 MHz, which results in a robust performance and eliminates potential problems with electromagnetic radiation limits above 30 MHz.<<ETX>>

Cyclic prefixed single carrier transmission with SFBC over mobile wireless channels

This letter proposes a space-frequency block-coded (SFBC) single-carrier frequency-domain equalization (SC-FDE) system. The transmit sequence of the proposed system is designed to have spatial and frequency diversities, and the corresponding combining receiver is derived under a minimum mean square error criterion. It is shown that the proposed system significantly outperforms the space-time block-coded SC-FDE system over fast-fading channels while providing lower computational complexity than orthogonal frequency division multiplexing combined with the SFBC.

Local distribution for IMTV

The local distribution system for an interactive multimedia television (IMTV) system builds on a fiber-to-the-curb (FTTC) architecture that delivers the IMTV signals to and from the home over telephone wiring and coaxial cable. The downstream IMTV channel, from the curb to the home, operates at a data rate of 51.84 Mbps, and the upstream channel, from the home to the curb, operates at a data rate of 1.62 Mbps.

Iterative cyclic prefix reconstruction and channel estimation for a STBC OFDM system

In order to prevent a loss of spectral efficiency due to the use of a cyclic prefix (CP), a CP reconstruction (CPR) method, such as residual intersymbol interference cancellation (RISIC), has recently been developed. In this letter, we apply the RISIC method to an Alamouti space-time block coded (STBC) orthogonal frequency division multiplexing (OFDM) system with insufficient CP. It is shown that in the STBC OFDM, tail cancellation as well as cyclic restoration of the RISIC should be repeated. An iterative channel estimation method for the STBC OFDM system with CPR is proposed. The performance of the proposed method is evaluated by computer simulation in a multipath fading environment.

Amplitude Clipping and Iterative Reconstruction of STBC/SFBC-OFDM Signals

As with orthogonal frequency-division multiplexing (OFDM), one main disadvantage of multi-input multi-output (MIMO) OFDM is the prohibitively large peak-to-average power ratio (PAPR) of transmitted signals on different antennas, which can be reduced by a deliberate amplitude clipping. However, clipping causes distortion that degrades the system performance. In this letter, we propose clipping noise mitigation techniques for space-time and space-frequency block coded (STBC/SFBC)-OFDMs. A new SFBC transmitter for clipped OFDM is proposed, and the optimum equalizer is derived for reconstruction of the clipped signals. Simulation results show that the proposed receivers effectively recover contaminated STBC/SFBC-OFDM signals with a moderate computational complexity.

Iterative Multiuser Detection with Spectral Efficient Protocol for Relay-Assisted SC-FDE

This letter proposes an iterative multiuser detection scheme using spectral efficient protocol for relay-assisted single- carrier frequency-domain equalization (SC-FDE). The proposed system achieves spatial diversity over fading channels in a distributed fashion. In the proposed system, two sources with user-specific interleavers access a relay simultaneously, which increases spectral efficiency of time-division multiple-access (TDMA)-based relay protocol. Interference from the other source is removed by an iterative detection method in the frequency domain at the destination. Simulation results show that the proposed system can obtain diversity gain without sacrificing spectral efficiency and approaches the single-user bound.

An Efficient Cyclic Prefix Reconstruction Technique for MIMO Single-Carrier Frequency-Domain Equalization

In this letter, an efficient cyclic prefix reconstruction (CPR) technique with turbo equalization is developed for a multi-input multi-output (MIMO) single-carrier frequency-domain equalization (SC-FDE) system. The proposed method consists of pre-processing estimation (PPE) and residual inter-carrier interference suppression (RICIS). The PPE is employed to compute initial values of MIMO turbo equalization, and the RICIS is used to mitigate residual intercarrier interference (ICI) after each iteration of the CPR. By applying the proposed method to MIMO SC-FDE system with insufficient cyclic prefix (CP), we can significantly improve its error performance, obtaining both the benefits of multiplexing gain and spectral efficiency gain

Local distribution for interactive multimedia TV to the home

This paper discusses a local distribution system for interactive multimedia TV (IMTV) to the home. The network architecture considered here id fiber to the curb, and local distribution of the IMTV signals to and from the home is provided on telephone wiring and coaxial cable. The downstream IMTV channel, from the curb to the home, operates at a data rate of 51.84 Mb/s, and the upstream channel, from the home to the curb, operates at a data rate of 1.62 Mb/s.