Bandwidth efficiency improvement for multi-carrier systems

Hamamura, Masanori; Tachikawa, Shin'ichi

doi:10.1109/pimrc.2004.1370834

Cited by 49 publications

(24 citation statements)

References 2 publications

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“…Usually, the OFDM receiver utilizes the whole duration ( f 0 T =1) of the OFDM signal, except the guard interval (GI), to recover the message symbols. It has been shown that for some types of high-compaction multicarrier modulation (HC-MCM) [14]- [17], we can recover the message symbols even when only a partial duration of the OFDM signal can be utilized at the receiver. Figure 1 shows the transmitter and receiver for the OFDM system with a partial signal.…”

Section: Model Of Ofdm System With Partial Signalmentioning

confidence: 99%

Collision Recovery for OFDM System over Wireless Channel

Hou

Hamamura

2007

IEICE Transactions on Fundamentals of Electronics, Communicatio

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SUMMARYWe present an effective method of collision recovery for orthogonal frequency division multiplexing (OFDM)-based communications. For the OFDM system, the modulated message data can be demodulated using the partial time-domain OFDM signal. Therefore, the partial time-domain signal can be adopted to reconstruct the whole OFDM timedomain signal with estimated channel information. This property can be utilized to recover packets from the collisions. Since most collisions are cases in which a long packet collides with a short packet, the collided part is assumed to be short. The simulated results show that the method can recover the two collided packets with a certain probability and can be developed to solve the problem of hidden terminals. This method will dramatically benefit the protocol design of wireless networks, including ad hoc and sensor networks.

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Section: Model Of Ofdm System With Partial Signalmentioning

confidence: 99%

Collision Recovery for OFDM System over Wireless Channel

Hou

Hamamura

2007

IEICE Transactions on Fundamentals of Electronics, Communicatio

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“…In [23], it has been concluded that the spectral efficiency of linear modulations with finite order constellations can be improved by reducing the spacing between adjacent signals, both in time and frequency domains. This technique has appeared in the literature in several names such as Fast OFDM (FOFDM) [24,25], Spectrally efficient FDM (SEFDM) [26], M-ary amplitude shift keying (M-ary ASK), High Compactions Multi-carrier Communications (HC-MCM) [27] etc. In [25], the first experimental demonstration of optical Fast-OFDM (FOFDM) system has been carried out with a reduced sub-carrier spacing equal to the symbol rate.…”

Section: Introductionmentioning

confidence: 99%

Frequency Packing for Interference Alignment-Based Cognitive Dual Satellite Systems

Chatzinotas

Sharma

Ottersten

2013

2013 IEEE 78th Vehicular Technology Conference (VTC Fall)

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Abstract-Interference Alignment (IA) has been considered a promising technique for spectral coexistence of different wireless systems in an underlay cognitive mode. Furthermore, Frequency Packing (FP) can be considered as an important technique for enhancing the spectrum efficiency in spectrum-limited satellite applications. In this paper, we consider a spectral coexistence scenario of a multibeam satellite and a monobeam satellite with the monobeam satellite as primary and the multibeam satellite as secondary. In this context, this paper focuses on examining the effect of FP on the performance of multi-carrier based IA technique. For this purpose, different IA techniques such as coordinated IA, uncoordinated IA and static IA have been considered. The effect of FP on the performance of different IA techniques in the considered scenario is evaluated in terms of system sum rate and primary rate protection ratio. It is shown that the system sum rate increases with the FP factor for all the techniques and the primary rate is perfectly protected with the coordinated IA technique even with dense FP.

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“…Parallel combinatory OFDM (PC-OFDM) was proposed in a previous article [9] and uses the technique of PC signaling, which has higher spectral efficiency and a lower bit-error rate (BER) than ordinary OFDM. Another technique that improves the spectral efficiency of OFDM is high-compaction multicarrier modulation (HC-MCM) [10]. This is a method of achieving high spectral efficiency by overlapping the carriers of the transmitted signal.…”

Section: Introductionmentioning

confidence: 99%

Two-stage decoding algorithm for unmodulated parallel combinatory high-compaction multicarrier modulation signals

Hayashi

Hamamura

2013

J Wireless Com Network

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A new decoding algorithm that consists of two decoding stages to reduce the computational complexity of maximum likelihood decoding for parallel combinatory high-compaction multicarrier modulation is proposed. The first decoding stage is responsible for a preliminary decision that serves to roughly find candidate messages using the QRD-M algorithm, and the second decoding stage is responsible for the final decision that reduces the error contained in the candidate and determines the message using the minimum value of the Hamming distances between the candidate and the replicas of the message. The complexity is considerably reduced by the proposed two-stage decoding algorithm at a cost of approximately 1.5 dB or less in E b /N 0 with respect to the bit-error rate of 10 −3 under the given parameter settings.

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Bandwidth efficiency improvement for multi-carrier systems

Cited by 49 publications

References 2 publications

Collision Recovery for OFDM System over Wireless Channel

Collision Recovery for OFDM System over Wireless Channel

Frequency Packing for Interference Alignment-Based Cognitive Dual Satellite Systems

Two-stage decoding algorithm for unmodulated parallel combinatory high-compaction multicarrier modulation signals

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