Performance analysis of time division broadcast protocol with incremental relaying and symmetric users

Abstract

SUMMARYThis paper investigates two‐way relaying with direct link transmission. We propose to combine incremental relaying (IR) with the time division broadcast protocol (TDBC) to form a new scheme, termed TDBC‐IR, to increase the spectral efficiency of TDBC. Assuming half‐duplex decode‐and‐forward relaying, the performance of three protocols, that is, TDBC, TDBC‐IR, and physical‐layer network coding (PNC), are studied and compared, in terms of outage probability, expected rate (ER), and diversity‐multiplexing tradeoff. First, we reveal that the outage probability performance of TDBC‐IR is the same as that of TDBC and better than that of PNC. Second, we compare the ER and diversity‐multiplexing tradeoff performance of the three protocols based on the derived outage probability. The numerical results reveal that (1) the ER of TDBC‐IR is greater than that of TDBC and PNC in the whole signal‐to‐noise ratio (SNR) region, that is TDBC‐IR has improved spectral efficiency performance; (2) the ER performance of TDBC is better than PNC in the low SNR region but worse in the high SNR region; (3) the maximum achievable diversity order of TDBC‐IR and TDBC are both two whereas that of PNC is one; (4) the maximum achievable multiplexing gain of TDBC‐IR is one, which is better than TDBC (its maximum achievable is 2/3) and achieves the maximum of PNC (its maximum achievable is one). Copyright © 2012 John Wiley & Sons, Ltd.

Performance of Dynamic Time Division Broadcast Protocol with Rateless Coding

“…Moreover, the transmission lengths of the first and second time slots are random depending on the channel quality of the direct link because the sources transmit in rateless coding way. Therefore, the transmission length of one-round information exchange is 2T DTDBC−RC when both S 1 and S 2 succeed in the first and second time slots (corresponding to State 2) or when R cannot decode successfully at least one source's message (corresponding to Case II in State 1), or is T when both S 1 and S 2 cannot decode successfully in the first and second time slots and R successfully decodes both sources' messages (corresponding to Case I in State 1); and (iii) we extend the equal-length time slot assumption in [7,8] to the case with unequal-length time slot in the paper (see Figure 1), i.e., both the first and second time slots are with length αT in TDBC-IR like DTDBC-RC (The protocol in [7,8] corresponds to the case when α = 1 3 for TDBC-IR in the paper.). Thus, the outage probability, expected rate, and DMT analysis for TDBC-IR in Section 3 is for the unequal-time length case.…”

“…This can be deduced by how the outage event occurs. We also note that for TDBC-IR in [7,8], the authors consider the case with three equal-length time slots.…”

“…To enhance throughput performance in relaying channel, incremental redundancy (IR)-based retransmission is commonly used by utilizing one-bit feedback indicating successful or failed decoding at the destination [4][5][6], and it has been incorporated in TDBC (i.e., TDBC-IR) to improve the throughput performance of TDBC [7,8] (Note that one retransmission is used in PNC in [9] to form a new protocol named PNC-IR, aiming to improve the outage performance. However, not only the outage performance but also the throughout performance of PNC-IR are improved by introducing one retransmission when compared with PNC.…”