A comparison of an OFDM system and a single carrier system using frequency domain equalization

SUMMARYThe present paper introduces frequency domain equalisation (FDE) as an efficient means for single-user detection (SUD) in universal mobile telecommunication systems (UMTS) handhelds. Such an SUD is, at least partially, able to remove multiple access interference (MAI) like a multi-user detector (MUD), however with several important advantages the operation principle of an FDE-SUD is simple and easy to understand, the FDE-SUD shows low numerical complexity and therefore, it is not power hungry like an MUD.The problem of applying FDE without zero-padding or cyclic-prefix insertion is solved by using the overlapcut method. In this paper we also prove that the performance of the FDE-SUD is practically identical to that of linear MUD for a fully loaded UMTS cell. Furthermore, armed with the idea of FDE for code division multiple access (CDMA), we can construct a common receiver structure for CDMA, time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM) and multi-carrier CDMA (MC-CDMA) systems. This is an extremely useful idea in enabling a software-defined radio (SDR) which can operate seamlessly in several environments such as UMTS, the IEEE 802.11a and WiMaX. FDE based receivers could be one important building-block for the next generation mobile communications.

Section: Software-defined Radio Based On Fdementioning

confidence: 93%

“…Falconer et al [2] and Witschnig et al [29], for example, mentioned the possibility to combine a single-carrier system using FDE in uplink and an OFDM system in downlink of a mobile communication system. However, since we have shown that FDE is also applicable in CDMA systems, we can then move even further.…”

Section: Software-defined Radio Based On Fdementioning

confidence: 98%

Frequency domain equalisation in CDMA detection

Martoyo

Jondral

2007

“…For OFDM, D is the IFFT block and Q is an ineffective identity matrix and vice versa for SC‐FDE. Both OFDM and SC‐FDE are cyclic prefix (CP) block transmission based techniques and utilise FFT and IFFT algorithms .…”

Section: System Modelmentioning

confidence: 99%

Capacity analysis of power line communication point‐to‐point and relay channels

Sheikh‐Hosseini

Hodtani

Molavi-Kakhki

2014

In this paper, we present a capacity analysis for broadband power line communication (PLC) channels, impaired by the Bernoulli-Gaussian impulsive noise, exploiting both orthogonal frequency division multiplexing (OFDM) and singlecarrier frequency-domain equalisation (SC-FDE) techniques. First, we investigate point-to-point communications and formulate the continuous signal model for OFDM and SC-FDE techniques in PLC environments and find the tight bounds derived for differential entropy of the non-Gaussian noise samples. Capacity bounds and a certain capacity result for pointto-point PLC systems are also computed. Then, we analyse the capacity in the presence of a relay terminal between the transmitter and the receiver. In this part, we assume correlated noises between the relay and the receiver and derive general upper bound and achievable rate using partial decode-and-forward coding strategy for PLC channels. We also show that the obtained bounds coincide in degraded and reversely degraded special cases. Finally, using two statistical divergences, we compare the distances of the Bernoulli-Gaussian and Middleton class A noise models from the normal distribution of their background part and show that the Middleton class A noise is nearer to the Gaussian background noise than the Bernoulli-Gaussian. Therefore, the capacity curve for Middleton class A noise is between the capacity for the Gaussian background noise and the obtained capacity for the Bernoulli-Gaussian model. The obtained capacity theorems are also illustrated numerically.

“…In many research works, orthogonal frequency division multiplexing (OFDM) has been employed as the antimultipath technique and the STBC designs have been performed accordingly . Despite its great academic and industrial success, OFDM suffers from several drawbacks such as large peak to average power ratio and high sensitivity to carrier frequency offsets …”

Section: Introductionmentioning

confidence: 99%

“…In order to address the OFDM limitations, SC‐FDE has already been used as an alternative for communications over multipath channels . Similar to OFDM, SC‐FDE is a cyclic prefix (CP)–based technique that utilizes computationally efficient blocks of fast Fourier transform (FFT) and inverse FFT (IFFT) at the receiver side .…”

Section: Introductionmentioning

confidence: 99%

Transceiver design for STBC transmission over MIMO multiple‐access SC‐FDE systems

Sheikh‐Hosseini

2018

This paper investigates the transceiver design for a multiple‐input multiple‐output multiple‐access system, J cochannel users each having Q antennas and an array‐processing receiver employing M receive antennas, in which the single‐carrier frequency‐domain equalization technique is used as the physical layer solution for the transmission of different space‐time block coding (STBC) schemes. Assuming quasi‐static fading model and no channel state information at the user terminals, a transceiver design is provided for this system utilizing M=J receive antennas for interference cancellation, frequency‐domain equalization, and detection of the users. First, this design is considered for orthogonal and generalized coordinate interleaved orthogonal design STBCs as 2 single‐symbol decodable STBC schemes and then extended to quasi‐orthogonal STBC as a double‐symbol decodable STBC scheme. For this extension, each quasi‐orthogonal system of J users and Q transmit antennas is converted to 2 orthogonal subsystems of J cochannel users each having Q antennas and then each subsystem is detected using the proposed method for orthogonal STBC transmission. Finally, the average bit error rate of the obtained designs is numerically illustrated for different STBC schemes with various numbers of users and transmitting antennas.