Preamble Design Using Embedded Signaling for OFDM Broadcast Systems Based on Reduced-Complexity Distance Detection

Abstract

Abstract-The second-generation digital terrestrial television broadcasting standard adopts the so-called P1 symbol as the preamble for initial synchronization. The P1 symbol also carries a number of basic transmission parameters, including the fast Fourier transform size and the single-input/single-output as well as multiple-input/single-output mode, to appropriately configure the receiver for carrying out the subsequent processing. In this paper, an improved preamble design is proposed, where a pair of training sequences is inserted in the frequency domain, and their distance is used for transmission parameter signaling. At the receiver, only a low-complexity correlator is required for the detection of the signaling. Both the coarse carrier frequency offset and the signaling can simultaneously be estimated by detecting the aforementioned correlation. Compared with the standardized P1 symbol, the proposed preamble design significantly reduces the complexity of the receiver while retaining high robustness in frequency-selective fading channels. Furthermore, we demonstrate that the proposed preamble design achieves better signaling performance than the standardized P1 symbol despite reducing the numbers of multiplications and additions by about 40% and 20%, respectively.Index Terms-Orthogonal frequency-division multiplexing (OFDM), preamble, second-generation digital terrestrial television broadcasting standard (DVB-T2), transmission parameter signaling (TPS).

Low-Complexity Signaling-Embedded Preamble Design Based on Relative Subcarrier Position

“…This section evaluates the performance of the proposed preamble compared with two conventional preambles for DVB-T2 [2] and DTMB-A [4], respectively. Fig.…”

“…Fig. 7 compares the signaling error rate (SER) of the proposed preamble with that of two conventional preambles over two dispersive channels (Brazil-B [4] and typical urban TU-6 [2, pp.174-175] channel models). It can be observed that the proposed preamble outperforms the preamble for DTMB-A and the s 1 signaling for DVB-T2, and achieves very similar performance as the s 2 signaling for DVB-T2 over both dispersive channels.…”

“…2, unlike the P1 preamble using different sequences to carry the signaling for DVB-T2, the preamble for DTMB-A dynamically selects the distance of two identical sequences c to convey the signaling. Each of these two sequences occupies the consecutive 255 subcarriers (L = 255T s ), and their variable distance ΔL (ranging from 0 to 127) is used to map to the 7-bit signaling [4], [5].…”

“…It is worth noting that the spatial modulation technique [6] relies on the on/off status of one specific antenna in MIMO systems to transmit extra bits, which implies that we can also adopt only one PBS with variable subcarrier position to carry signaling, but why the other fixed PBS is used in the proposed preamble? The reason is that large carrier frequency offset (CFO) will cause the cyclic shift of the subcarriers of the preamble [4], so the fixed PBS at the fixed subcarrier position k = N/2 is adopted for CFO detection. Consequently, the other PBS with the variable subcarrier position at k = N/2 − Δk can be used to carry the specific signaling according to the RSP Δk between the fixed PBS and the variable PBS.…”

“…This preamble selects two sequences from two orthogonal sets to carry several signaling bits, so the receiver requires multiple sequence correlations for signaling demodulation, which yields a large amount of computation [2], [3]. To reduce the complexity, an improved preamble design was proposed in [4], where the signaling is carried by the distance of two special sequences in the frequency domain, and the signaling can be demodulated by distance detection at the receiver. This preamble reduces Manuscript the required number of sequence correlations due to the used special sequences are deterministic.…”