Abstract-A multiway relay network (mRN), which is widely employed in the literature, is extended to represent a larger number of practical scenarios, such as a vehicular ad hoc network (VANET). For the proposed system, generalized multiway relay network (g-mRN), three transmission strategies are presented and analyzed in terms of effective rate, for different numbers of users. Assuming that the average signal-to-noise ratio (SNR) is known to the transmitters, the maximum effective rate is obtained through the optimal choice of the message rates. We also derive the effective rate for fixed message rates. Numerical results show that the best strategy under the optimal message rates is the one in which all users transmit simultaneously in the multiple access phase. But when considering fixed message rates, the best transmission strategy depends upon the SNR. These results are important in that they can be used as guidelines for selecting the right strategy and message rates depending on the situation.Index Terms-Multiway relay network, Effective rate, Message rate, VANET.
N e w good high-rate p u n c t u r e d convolutional codes (PCC's) are presented. While any previously k n o w n PCC was derived b y puncturing a low-rate time-invariant m o t h e r code, the n e w PCC's are s h o w n t o be derived b y puncturing a periodically time-varying convolutional code (PTVCC) acting as the mother code. To find the n e w PCC's, w e first show that a n y PTVCC (hence, a n y PCC) is equivalent to a t y p e of time-invariant convolutional code.Focusing on a fixed unit-memory (UM) code, w e also s h o w that under certain conditions there exists a PTVCC along w i t h a p u n c t u r i n g pattern that is equivalent to that WM code. A combinatorial optmization a l g o r i t h m is then used to search for the n e w good WM codes €or which equivalent PCC's do exist. We observe that the n e w PCC's compare favorably to the previously known PCC's in several respects.
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