The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Optical wireless systems have attracted much attention, because they allow high speed transmission without electromagnetic interference. Orthogonal frequency division multiplexing (OFDM) can send multiple high speed signals by using orthogonal carrier frequencies. Recently, studies have focused on the optimal OFDM technique for optical wireless systems. When using OFDM, one important issue is the...
We have been developing a very high throughput WLAN system based on IEEE802.11ac's criteria. It combines MIMO and OFDM technology to provide throughput over 1 Gbps for 150 feet propagation distance by using 80MHz of bandiwdth on 5GHz frequency band. 4 by 5 antennas MIMO is set to get 2nd-order diversity gain to maintain high throughput and performance. Greenfield preamble with novel phase rotation...
Sampling frequency offset (SFO) that occurs due to a sampling frequency mismatch between the transmitter and receiver oscillators is one of the main problem in the orthogonal frequency division multiplexing (OFDM) based digital terrestrial television (DTTV) system. The SFO can cause an intersymbol interference and an intercarrier interference that may degrade the performance of an OFDM system and...
In this paper, we evaluate the performance of the next generation standard IEEE 802.11ac wireless local area network (WLAN) system. IEEE 802.11 for the first time will employ downlink multi-user multi-input multi-output (MU-MIMO) technology. Precoding techniques greatly influences the performance of MU-MIMO transmission. We measure these improvements when realistic channel conditions are applied....
This paper shows the design and ASIC implementation of a 802.11n WLANs 4×4 MIMO OFDM PHY transceiver. The system supports the maximum data rate of 600Mbps. The MMSE-SQRD SIC MIMO decoder scheme, which has high BER performance and acceptable hardware cost, is implemented. To meet the required high throughput rate, parallel processing Scrambler/Descrambler, parallel processing BCC, and radix-4 soft-decision...
This paper discus an ASIC implementation of puncture and SSP for MIMO IEEE 802.11n 4×4 MIMO Wireless LAN system. We also describe its receiver counterpart block, which is SSDP and Depuncture. The biggest challenge of this work is 72 modes operation that need to be supported. The design is implemented on 90nm ASIC CMOS technology. Synthesis result for puncture and SSP reveal that the logic area is...
Long Term Evolution (LTE) physical layer identity can be recognized either in frequency domain or time domain. In this paper we serve some comparisons in term of complexity, latency, and recognition probability. As a result, frequency domain detection has superiority on performance for SNR higher than 3dB on all channel models, as well as lower latency than time domain scheme one. However, it requires...
Long Term Evolution (LTE) is one of radio access technology that has been intensively studied in 3GPP standard group to support instantaneous downlink and uplink peak data rates of 100 Mb/s and 50 Mb/s within 20 MHz downlink and uplink spectrum allocations, respectively. Employing OFDMA and scalable bandwidth scheme in downlink access impact on increasing cell search complexity. In this paper we propose...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.