Synchronization Receiver for OFDM-Based FM Broadcasting Systems

Abstract

The digital radio mondiale (DRM) consortium is now preparing to test and verify the design of DRM plus, prior to standardization, produce a revision to the existing DRM system specification. This paper presents an overview of the OFDM-based DRM system, planned to operate in FM bands, utilizing important receiver aspects, such as timing and frequency synchronization, which can provide benefits to the overall system performance. In particular, algorithms are devised or selected for the sequential estimation of symbol timing and carrier frequency offsets by exploiting the structure of the data and pilot. The performance of using the proposed algorithms is demonstrated via several examples in the channel models for FM bands.

Robust Sampling Frequency Offset Estimation for OFDM over Frequency Selective Fading Channels

“…In this section, we briefly revisit the conventional SFO estimation algorithms used n the DRM system [12][13][14] and focus on the MSE performance of the considered estimation schemes. In [12,13], the differential relation among FRCs is used, while [14] exploits two adjacent OFDM blocks where the sets of pilot subcarriers are located symmetrically and distributed equally around the DC carrier.…”

“…In [12,13], the differential relation among FRCs is used, while [14] exploits two adjacent OFDM blocks where the sets of pilot subcarriers are located symmetrically and distributed equally around the DC carrier. In order to benchmark the proposed estimation scheme, a robust estimation algorithm which archives frequency estimates in closed-form [22] can be applied to the DRM system.…”

“…Since (4) and (7) are based on the limited FRCs, the basic concept reported in [22,23] can be straightforwardly extended to the DRM system for further enhancing the estimation performance, which uses the GRC as the pilot symbol [14]. Depending on DRM robustness mode and OFDM symbol index l, GRC pattern is repeated in the frequency and time directions.…”

“…As discussed in [22,23], the condition of small SFO and less frequency selectivity ensures the unbiasedness of (14). To overcome this drawback, the robust SFO estimation scheme to the presence of the CFO along with frequency selectivity will be suggested in the following section.…”

“…If not properly estimated and compensated, the frequency error may limit the performance of an OFDM system. Therefore, time and frequency synchronization has been one of the major concerns of the OFDM-based DRM system [10][11][12][13][14][15][16]. Several schemes have been proposed in literature to estimate the SFO in frequency domain in the DRM system [12][13][14][15][16].…”