Statistic-Based Magnitude Determination of Impulse Sample in Impulse Postfix OFDM Systems

Abstract

Instead of pilot tones, the impulse sample is exploited for channel estimation in Impulse Postfix OFDM systems [1]. As the magnitude of impulse sample is increased, the accuracy of channel estimation can be enhanced, but it may significantly increase the PAPR of generated OFDM symbols. In this letter, based on the statistical analysis of the generated OFDM symbol, we propose a decision scheme for determining the magnitude of impulse sample. By using the proposed scheme, we can determine the magnitude of impulse sample that provides the enhancement of BER performance as well as the avoidance of PAPR increase. The validation of the proposed scheme is demonstrated by computer simulations.

The impact of impulse postfix length on the BER performance of IP‐OFDM systems

“…The IP-OFDM proposed in [1,2] is a modified OFDM system, which adds an impulse sample and several zero samples at the end of a ZP-OFDM symbol block for time-domain channel estimation. The simplified block diagram for the transmitter part of IP-OFDM system is shown in Figure 1.…”

“…An impulse postfix orthogonal frequency division multiplexing (IP-OFDM) system, which performs channel estimation in time domain by exploiting the IP instead of pilot tones, has recently been introduced [1,2]. The IP-OFDM system exploits the IP, which consists of a high power impulse sample and several zero samples at the end of a zero padded-OFDM (ZP-OFDM) [3] symbol block, to estimate channel impulse response (CIR) in time domain.…”

“…The IP-OFDM system exploits the IP, which consists of a high power impulse sample and several zero samples at the end of a zero padded-OFDM (ZP-OFDM) [3] symbol block, to estimate channel impulse response (CIR) in time domain. As shown in [1,2], without loss of data rates, the IP-OFDM system achieves the enhanced bit error rate (BER) performance compared with that of conventional OFDM systems.…”

Power boosting factor determination in impulse postfix‐OFDM‐based positioning system

“…One complete IP-OFDM symbol adds an impulse postfix (IP), which consists of a high power impulse sample and several zero samples at the end of an OFDM symbol block, to estimate channel impulse response (CIR) in time domain. Compared with the conventional cyclic prefix OFDM and zero padding OFDM, which adopt pilots for channel estimation [2], the IP-OFDM system achieves the enhanced BER performance [1,2] because of the robustness of IP-based channel estimation against time and frequency selective channel. Moreover, the IP-OFDM has another key advantage of low complexity, because the CIR is obtained directly by using the impulse symbol in the time domain, which is essential for channel estimation.…”

“…With the assumption that the total transmit power is fixed, the accuracy of channel estimation can be enhanced by increasing the power of impulse sample, which will benefit the communication quality; nevertheless, if relatively high power was assigned on the impulse sample, the BER performance of IP-OFDM system will likely be degraded because the power distributed to data samples is insufficient; meanwhile, huge amplitude of IP will aggravate peak-to-average power ratio (PAPR) issue, which is a common problem in OFDM system [3][4][5]. Thus, PBF determination has been paid much attention as an important issue in IP-OFDM system [2,6,7]. For instance, in [6], a nonlinear high power amplifier (HPA) and nonideal predistorter are considered in a practical IP-OFDM system, and the impact of nonlinear HPA on the determination of the PBF of IP and the BER performance are analyzed.…”