As a high-rate alternative of impulse radio (IR) ultrawideband (UWB) communications, analog and digital multicarrier UWB radios with coherent detection have been introduced. In this paper, we investigate digital multicarrier differential (MCD) modulation and demodulation schemes for UWB communications. In our approach, the differential encoding and decoding are carried out across multiple digital carriers in the frequency domain. Hence, channel estimation is bypassed by using neighboring carriers as reference carriers. Compared with the transmitted reference TR-UWB which relies on delaying and correlating the received signal segments in time domain, our MCD-UWB avoids the need for analog delay elements. In addition, our digital-carrier based approach does not incur any spectrum expansion. We also show that our approach enables variable data rates, and remains operational even in the presence of severe interframe interference (IFI). In addition, the small spacing between differentially encoded carriers ensures that the data rate is not limited by the channel coherence bandwidth. Furthermore, our schemes are flexible in providing variable-rate transmissions. Simulations are also carried out to corroborate our theoretical analysis.
|Original language||English (US)|
|Number of pages||12|
|Journal||IEEE Transactions on Signal Processing|
|State||Published - Jan 2008|
Bibliographical noteFunding Information:
Manuscript received September 5, 2006; revised April 17, 2007. The associate editor coordinating the review of this paper and approving it for publication was Dr. Kostas Berberidis. This work was supported by the National Science Foundation under Grant ECS-0621879. Parts of the results in this paper have been accepted by the IEEE International Conference on Ultra Wideband 2006 and the IEEE Globecom 2006.
- Differential modulation and demodulation
- Digital multicarrier
- Ultrawideband (UWB)