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Efficient utilization of the IEEE 802.11ac 80 and 160 MHz channels has been considered recently. In this paper it is shown, how the successive interference cancellation (SIC) method can be used in a 80 MHz receiver to reject the interfering legacy 802.11a/n OFDM signal occupying any secondary 20 MHz channel inside the 80 MHz 802.11ac channel. The method can be also utilized in 160 MHz receiver in a similar manner. The simulation shows, that if the conditions specified in the paper are fulfilled then no frequency guard band is necessary between the interfering OFDM signal and the desired OFDM signal occupying the remaining part of the 802.11ac 80 MHz channel. Both OFDM signals, the interfering and the desired one, are transmitted with no symbol timing synchronization. The simulation results show that two or three iterations are enough to completely reject the interfering OFDM signal by the 80 MHz (or 160 MHz) receiver.

This paper is to contribute a new dynamic channel access method for wireless local area networks. It allows a station accessing the 80 or 160 MHz channel to capture every idle non-primary 20 MHz channel along with the primary 20 MHz channel, whereas the number of channel configurations in which the station can transmit according to the 802.11ac standard is strictly limited. Simulation results shown in the paper prove the proposed access method to be superior to the method provided by the 802.11ac standard in terms of average network throughput. What is important for legacy reasons, the proposed method employs the conventional clear channel assessment function to determine which of the 20 MHz channels are idle and which are busy. The paper proposes a new receiver design that is able to reject the adjacent channel interference, arising as a result of the presence of the legacy 802.11a/n station signals inside the 80 or 160 MHz accessed channel.

This paper focuses on the applicability of BitInterleaved Space-Time Coded Modulation with Iterative Decoding (BI-STCM-ID) to Wireless Local Area Networks (WLAN). A new intuitive space-time diversity scheme, which ensures a low error rate for small signal-to-noise ratios (SNR) and good asymptotic performance, is provided. The presented technique can ensure compatibility with today's WLAN specifications. The EXtrinsic Information Transfer Chart (EXIT) and the bit error rate (BER) simulations confirm its usefulness.decoding in WLAN systems is described in Section III. The novel concept of space-time coding is presented in Section IV. High usefulness of the proposed solution is verified by the EXIT chart and the system simulation. Moreover, the asymptotic coding gain is evaluated and the asymptotic BER bound is drawn. In section V the obtained results are summarized.

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