Abstract
The emerging orthogonal time frequency space (OTFS) modulation technique has shown its superiority to the current orthogonal frequency division multiplexing (OFDM) scheme, in terms of its capabilities of exploiting full time-frequency diversity and coping with channel dynamics. The optimal maximum a posteriori (MAP) detection is capable of eliminating the negative impacts of the inter-symbol interference in the delay-Doppler (DD) domain at the expense of a prohibitively high complexity. To reduce the receiver complexity for OTFS scheme, this paper proposes a variational Bayes (VB) approach as an approximation of the optimal MAP detection. Compared to the widely used message passing algorithm, we prove that the proposed iterative algorithm is guaranteed to converge to the global optimum of the approximated MAP detector regardless the resulting factor graph is loopy or not. Simulation results validate the fast convergence of the proposed VB receiver and also show its promising performance gain compared to the conventional message passing algorithm.
| Original language | English |
|---|---|
| Article number | 9082873 |
| Pages (from-to) | 7976-7980 |
| Number of pages | 5 |
| Journal | IEEE Transactions on Vehicular Technology |
| Volume | 69 |
| Issue number | 7 |
| Early online date | 30 Apr 2020 |
| DOIs | |
| Publication status | Published - Jul 2020 |
| Externally published | Yes |
Bibliographical note
This work was supported by the Australia Research Council Discovery Project DP190101363 and Linkage Projects LP 160100708 and LP170101196. The work of D. W. K. Ng was supported by the UNSW Digital Grid Futures Institute, UNSW, Sydney, under a cross-disciplinary fund scheme and by the Australian Research Council’s Discovery Project DP190101363.Keywords
- low complexity
- Orthogonal time frequency space
- receiver design
- variational Bayes