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) |
|---|---|
| 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