With the rapid growth of frequency-hopped (FH) wireless networks, interference due to frequency collisions has become one of the main performance-limiting challenges. This paper proposes a novel multiuser detection method for joint hop timing and frequency estimation, which is capable of unraveling and demodulating multiple FH transmissions in the presence of collisions and unknown hop patterns without retransmission. The method is based on the principle of dynamic programming (DP) coupled with two-dimensional harmonic retrieval (2-D HR) or low-rank trilinear decomposition, and it remains operational even with multiple unknown hop rates, frequency offsets, and asynchronism. The model is based on frequency-shift keying (FSK) and phase-shift keying (PSK) modulation, but the algorithms are also evaluated with Gaussian minimum-shift keying (GMSK) modulation and shown to be robust,
Bibliographical noteFunding Information:
Manuscript received April 19, 2004; revised September 9, 2004; accepted October 22, 2004. The editor coordinating the review of this paper and approving it for publication is V. K. Bhargava. This work was supported by Army Research Office (ARO) DAAD19-03-1-0228 and the Army Research Laboratory (ARL) Communications & Networks Collaborative Technology Alliance (CTA). Earlier versions of parts of this paper appeared in Proceedings of the ICASSP 2003 and Proceedings of the SPAWC 2003.
- Collision resolution
- Frequency hopping
- Harmonic retrieval (HR)
- Multiuser detection
- Timing estimation