Pilot assisted synchronization for wireless OFDM systems over fast time varying fading channels

Kapoor, S.; Marchok, D.J.; Huang, Yih-Fang

doi:10.1109/vetec.1998.686122

Cited by 38 publications

(22 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the proposed scheme can be implemented with partial pilot symbol settings that has less restriction on OFDM pilot symbol design. More specifically, for partial-pilot systems, the pilot pattern can be designed to facilitate effective channel estimates [14], [17], [23]. Once successive channel estimates are transformed into time domain, their phase rotation can be used to calculate the CFO.…”

Section: Simulation Results and Analysismentioning

confidence: 99%

“…In this paper, we focus on the problem of fine carrier synchronization. For fine carrier synchronization, CFO estimation can be done in either the time domain [13] or the frequency domain [14], [8], [15]. Time-domain schemes are based on time-domain correlation of the received signal, while frequency-domain schemes are based on using the frequencydomain phase information in consecutive OFDM symbols.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

Zhou¹,

Malipatil²,

Huang

2008

IEEE Trans. Wireless Commun.

View full text Add to dashboard Cite

Section: Simulation Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

Zhou¹,

Malipatil²,

Huang

2008

IEEE Trans. Wireless Commun.

View full text Add to dashboard Cite

“…Using only the mth pilot tone, an unbiased estimate of the CFO is constructed from a block of L symbols as [3,5],…”

Section: Typical Pilot Tones For Cfo Estimationmentioning

confidence: 99%

Clustered pilot tones for carrier frequency offset estimation in OFDM systems

Zhang

Xia

Ching

2007

IEEE Trans. Wireless Commun.

View full text Add to dashboard Cite

A new pilot tone placing and pilot sequence design is proposed to compensate the carrier frequency offset (CFO) in OFDM systems. Unlike the conventional approach where isolated pilot tones are used, in this paper every two pilot tones are clustered as a group and these groups are equally spaced. The pilot sequence is carefully designed, of which the left hand sided pilot symbol in each cluster is antipodal with the right hand sided one. The performance in terms of the pilot channel interference ratio (CIR) can be significantly improved by the proposed pilot scheme. Theoretical analysis shows that the clustered pilot tones can give a substantially lower CFO variance than that of the isolated pilot tones. Simulation results are presented to verify our newly proposed theory.

show abstract

“…Unlike uplink TDMA systems in which remote units transmit in bursts in specified periodic timeslots, uplink OFDMA can be made synchronous using the method of loop timing [12]. Fig.…”

Section: A Uplink Multiple Access Using Ofdmmentioning

confidence: 99%

“…To overcome frequency selective fading across the signal bandwidth, multiple pilots can be used. While conventional baseband digital phase-locked-loops can be used for operation over slowly time-varying channels, other techniques are used for frequency acquisition and tracking for operation over fast time-varying channels; see, e.g., [3] and [12]. The local timing reference for mobile transceivers are usually derived from a voltage controlled crystal oscillator (VCXO), which provides the timing reference for the receiver A/D, transmitter D/A, and all radio frequency (RF) circuitry.…”

Section: A Uplink Multiple Access Using Ofdmmentioning

confidence: 99%

Adaptive interference suppression in multiuser wireless OFDM systems using antenna arrays

Kapoor¹,

Marchok

Huang

1999

IEEE Trans. Signal Process.

Self Cite

View full text Add to dashboard Cite

Abstract-This paper considers the problem of mitigating fading and interference in wireless orthogonal frequency division multiplexing (OFDM) multiple access communication systems. Applications include cellular mobile radio, wireless local loop, and wireless local area networks. The effect of interchannel interference (ICI) arising from time-selective fading and frequency offsets and co-channel interference (CCI) is analyzed. A loop-timing method that enables a synchronous uplink between multiple mobile transceivers and a base-station is described. Adaptive antenna arrays are utilized at the base for uplink reception, and optimum array combining based on the maximum SINR criterion is used for each subchannel over slowly timevarying channels. For operation over fast time-varying channels, a novel two-stage adaptive array architecture that incorporates combined spatial diversity and constraint-based beamforming is presented. While ICI alone is most effectively overcome by spatial diversity, combined beamforming and diversity are most effective to combat CCI in the presence of fading. The overall method is suitable for real-time implementation and can be used in conjunction with traditional coding schemes to increase the link-margin.Index Terms-Adaptive arrays, interference suppression, OFDM.

show abstract

Pilot assisted synchronization for wireless OFDM systems over fast time varying fading channels

Cited by 38 publications

References 7 publications

OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

Clustered pilot tones for carrier frequency offset estimation in OFDM systems

Adaptive interference suppression in multiuser wireless OFDM systems using antenna arrays

Contact Info

Product

Resources

About