Abstract
A generalized frequency-hopping (GFH) orthogonal frequency-division multiple-access (OFDMA) system is developed in this paper as a structured long code direct-sequence code-division multiple-access (DS-CDMA) system in order to bridge frequency-hopped multicarrier transmissions with long code DS-CDMA. Through judicious code design, multiuser interference is eliminated deterministically in the presence of unknown frequency-selective multipath channels. Thanks to frequency-hopping, no single user suffers from consistent fading effects and constellation-irrespective channel indentifiability is guaranteed regardless of channel nulls. A host of blind channel estimation algorithms are developed trading off complexity with performance. Two important variants, corresponding to slow- and fast-hopping, are also addressed with the latter offering symbol recovery guarantees. Performance analysis and simulation results illustrate the merits of GFH-OFDMA relative to conventional OFDMA and long code DS-CDMA with pseudorandom noise codes and RAKE reception.
Original language | English (US) |
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Pages (from-to) | 721-733 |
Number of pages | 13 |
Journal | IEEE Transactions on Communications |
Volume | 49 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2001 |
Externally published | Yes |
Keywords
- Blind channel estimation
- Frequency-hopping
- Multicarrier CDMA
- Multipath fading channels
- Spread spectrum systems
ASJC Scopus subject areas
- Electrical and Electronic Engineering