SC-FDE

About: SC-FDE is a research topic. Over the lifetime, 438 publications have been published within this topic receiving 7547 citations.

SC-FDE V-BLAST system concept for MIMO over satellite with antenna misalignment

Abstract: For fixed satellite services (FSS) the performance of a single carrier — frequency domain equalizer (SC-FDE) MIMO system concept for line of sight (LOS) MIMO satellite channels is evaluated for the case of orthogonal and nearly orthogonal channels. The channel orthogonality is achieved by adjusting the phase angles within the channel transfer matrix through the LOS path distance which the signals have to travel between the respective transmit-receive antenna pair. This strategy finally leads to locally specific antenna arrangements needed for orthogonal channels with identical eigenmodes and maximum spatial multiplexing gain. For this particular type of channel a system has recently been proposed which revealed a very good performance in terms of bit error rate (BER) and mutual information. However, once the MIMO system has been optimized this way, practical impairments such as movements and maneuvers of the satellite or imperfect antenna arrangements of the user terminals might again cause a violation of the channel orthogonality. In this case the system performance suffers from spatial co-channel interference between the MIMO signal streams, which after all reduces the achievable throughput. This is analyzed and quantified in the paper for a typical scenario, and improvement potential is revealed by the application of a V-BLAST successive interference cancelation (SIC) scheme together with zero-forcing channel equalization.

SC-FDE with soft packet combining ARQ techniques for interference-limited UWB systems

Abstract: SC-FDE (Single-Carrier with Frequency-Domain Equalization) together with soft packet combining ARQ techniques (Automatic Repeat reQuest) was shown to be effective for broadband wireless systems with deep fading effects such as those inherent to shadowing. However, they are not suitable to cope with strong interference effects, especially when the channel remains fixed. In this paper, we consider UWB (Ultra Wide Band) systems employing SC-FDE techniques in the presence of strong interference signals that occupy a significant part of the transmission band and we propose suitable soft combining ARQ schemes. Our techniques are able to cope with strong interference levels as well as deep fading, even for fixed channels.

New Training Sequence Structure for Zero-Padded SC-FDE System in Presence of Carrier Frequency Offset

Abstract: Frequency domain equalization (FDE) is an attractive solution for wireless broadband transmission because of its strong capability in handling multipath environment. However, frequency domain channel estimation suffers from the inter-carrier interference(ICI) caused by carrier frequency offset (CFO). In this paper, we proposed new training sequence structure for channel estimation to reduce the estimation errors caused by residual CFO. The proposed new training sequence structure can be easily obtained from any existing channel training sequences without introducing significant changes to their original property. Simulation results show that, this scheme can efficiently reduce the channel estimation errors in FDE system, and improve the system performance.

Power Efficient MIMO SC-FDE Transmission Using Magnitude Modulation Techniques

Abstract: Polyphase magnitude modulation (MM) has been shown to be a robust and effortless mean to improve the efficiency of a transmitter's high power amplifier (HPA), due to the real-time reduction of the peak to average power ratio (PAPR). MM's technique flexibility allows us to include the MM system on any existing single-carrier (SC) based transmission system with clear benefits on the achieved bit error rate \emph{vs} overall signal power to noise ratio. This paper analyzes the efficiency of MM when added to a multi- input multi-output (MIMO) system, using a block-based SC transmission combined with iterative block decision feedback equalization (IB-DFE). To improve the IB-DFE performance for low power signals, we consider an additional scheme where low-density parity-check (LDPC) coding and turbo equalization are added. Simulation results show a net power efficiency enhancement, particularly for systems with channel coding, confirming MM as a major asset for high performance communication systems.

Performance of an SC-FDE SATCOM System in Block-Time-Invariant Orthogonal MIMO Channels

Abstract: A multiple-input multiple-output (MIMO) satellite communications system for fixed-satellite services (FSS) is considered The MIMO Line-of-Sight (LOS) satellite channel is optimized to achieve maximum spectral efficiency This requires an orthogonal MIMO channel matrix, ending up with large antenna spacing of the ground terminal antennas As the main drawback, considerable propagation delays between the MIMO paths are observed, and the MIMO signal sub-streams interfere asynchronously in the order of several tens or hundreds of a symbol duration at the receiver To cope with these delays, we propose a system architecture that uses a sufficiently large guard-interval or cyclic prefix between successive data blocks The delay equalization at the receiver is then performed by a zero-forcing frequency domain equalizer for single-carrier transmission (SC-FDE) Thanks to the orthogonality of the considered MIMO channel, the SC-FDE architecture achieves even perfect spatial equalization of the multiplexed signal streams at considerably low implementation effort The capacity reduction caused by the guard-interval is, moreover, mitigated by long data blocks, which can be used because of the long channel coherence times in FSS applications The system concept reveals superior BER and transinformation performance, which is verified through fair comparison with current single-input single-output (SISO) systems If the channel orthogonality is violated through narrow antenna spacing, the system performance degrades dramatically