Distributed space‐time block codes with embedded adaptive AAF/DAF elements and opportunistic listening for multihop power line communication networks

Abstract

SUMMARYWe consider the multihop power line communication (PLC) networks of one source, two repeaters, and one destination. In the previous scheme, when the repeaters receive the retransmission data from the source, they use the traditional distributed space-time block code (DSTBC) with all decode-and-forward (DAF) elements to transmit the data, and they do not consider the incorrect decoding. The original contribution is that we propose a novel DSTBC scheme with embedded adaptive DAF/amplify-and-forward (AAF) elements for data retransmission in multihop PLC networks with existing opportunistic listening (OL) protocols. The new scheme has two types (instead of only one type as in the previous scheme), and, in the second type, the coding matrix for data retransmission can use either all DAF elements or hybrid AAF/DAF elements depending on the correctness of OL results. The advantage is to avoid a loss of diversity because of incorrectly received data at the relays. The effectiveness of the proposed scheme is shown in the simulation results. For the impulsive noise parameter δ = 0.8 and worst case background noise (narrowband interference and colored noise) at bit error rate 10 À3 , our proposed system has 1 dB gain over the previous scheme with the traditional DSTBC with all DAF elements.

Time diversity scheme and adaptive signal clipping with blanking applied to G3 systems for narrowband power‐line communications

“…The use of the LDPC code detection technique thus approximates the behavior of LT codes over an erasure channel and prevents errors from propagating during the LT decoding process. Furthermore, time diversity can be combined with spatial diversity to further improve PLC systems . The author of a previous study suggests that a space‐time coded multiple‐input and single‐output configuration can outperform traditional single‐input single‐output PLC systems.…”

“…In the context of low‐voltage networks, this type of space‐time diversity technique has been achieved by transmitting the PLC signal over the three conductors of the three‐phase electrical network (spatial diversity) to a single receiver and using time‐division multiplexing (time diversity). Space‐time diversity has also been applied in the form of distributed space‐time block code in systems consisting of a PLC transceiver and a series of repeaters that are either set with an adaptive hybrid amplify‐and‐forward mode or decode‐and‐forward mode …”

“…Furthermore, time diversity can be combined with spatial diversity to further improve PLC systems. 18,19 The author of a previous study 18 suggests that a space-time coded multiple-input and single-output configuration can outperform traditional single-input single-output PLC systems. In the context of low-voltage networks, this type of space-time diversity technique has been achieved by transmitting the PLC signal over the three conductors of the three-phase electrical network (spatial diversity) to a single receiver and using time-division multiplexing (time diversity).…”

“…Space-time diversity has also been applied in the form of distributed space-time block code in systems consisting of a PLC transceiver and a series of repeaters that are either set with an adaptive hybrid amplify-and-forward mode or decode-and-forward mode. 19 Nonlinear preprocessing techniques that include clipping, nulling (blanking), hybrid clipping/blanking, and deep clipping are typically used at the transmitter of OFDM systems to reduce the peak-to-average power ratio but can also be used at the receiver of communication systems when the channel is affected by impulsive noise (IN) such as in the case of PLC. [20][21][22][23] The signal clipping method involves limiting the possible amplitude values of a waveform to a specified threshold value T c .…”

Widely linear channel estimation for LD‐STBC MB‐OFDM UWB systems

“…Among the MIMO techniques used in MIMO MB‐OFDM UWB systems, Linear Dispersion Space‐Time Block Codes (LD‐STBCs), proposed in , play important roles because they can achieve full spatial diversity. These codes have been extensively investigated in the literature . In this paper, we introduce the LD‐STBC MB‐OFDM UWB system.…”