Abstract
The analysis of the channel capacity in the absence of prior channel knowledge (noncoherent channel) has gained increasing interest in recent years. Yet, the noncoherent channel capacity is still unknown for the general case. In this paper, we derive bounds on the capacity of the noncoherent, underspread complex Gaussian, orthogonal frequency division multiplexing, wide sense stationary channel with uncorrelated scattering, under a peak power constraint or a constraint on the second and fourth moments of the transmitted signal. These bounds are characterized only by the system signal-to-noise ratio (SNR) and by a newly defined quantity termed effective coherence time. Intuitively, the effective coherence time can be interpreted as the length of a block in the block-fading model in which a system with the same SNR will achieve the same capacity as in the analyzed channel. Unlike commonly used coherence time definitions, it is shown that the effective coherence time depends on the SNR, and is a nonincreasing function of it. We show that for low SNR, the capacity is proportional to the effective coherence time, while for higher SNR, the coherent channel capacity can be achieved provided that the effective coherence time is large enough.
| Original language | English |
|---|---|
| Article number | 6259855 |
| Pages (from-to) | 6446-6470 |
| Number of pages | 25 |
| Journal | IEEE Transactions on Information Theory |
| Volume | 58 |
| Issue number | 10 |
| DOIs | |
| State | Published - 2012 |
Bibliographical note
Funding Information:Manuscript received September 15, 2010; revised May 24, 2011; accepted May 14, 2012. Date of publication August 03, 2012; date of current version September 11, 2012. This work was supported by the Italian Ministry of Education, University and Research under project PRIMO. This paper was presented in part at the 2008 IEEE Convention of Electrical and Electronics Engineers. I. Bergel is with the School of Engineering, Bar-Ilan University, 52900 Ramat-Gan, Israel (e-mail: [email protected]). S. Benedetto is with the Dipartimento di Elettronica—Politecnico di Torino, 10129 Torino, Italy (e-mail: [email protected]). Communicated by S. Verdú, Executive Editorial Board Member. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TIT.2012.2205662
Funding
Manuscript received September 15, 2010; revised May 24, 2011; accepted May 14, 2012. Date of publication August 03, 2012; date of current version September 11, 2012. This work was supported by the Italian Ministry of Education, University and Research under project PRIMO. This paper was presented in part at the 2008 IEEE Convention of Electrical and Electronics Engineers. I. Bergel is with the School of Engineering, Bar-Ilan University, 52900 Ramat-Gan, Israel (e-mail: [email protected]). S. Benedetto is with the Dipartimento di Elettronica—Politecnico di Torino, 10129 Torino, Italy (e-mail: [email protected]). Communicated by S. Verdú, Executive Editorial Board Member. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TIT.2012.2205662
| Funders | Funder number |
|---|---|
| Ministero dell’Istruzione, dell’Università e della Ricerca |
Keywords
- Channel capacity
- frequency-selective fading channel
- time-varying channels