Advanced Wireless Communication

To expose the students to the importance of improving capacity of wireless channel using MIMO

1. Subject handled by Parameswari.A EC8092- Advanced Wireless Communication

2. OBJECTIVES:   To expose the students to the importance of improving capacity of wireless channel using MIMO To enable understanding of channel impairment mitigation using space-time block and Trellis codes To teach advanced MIMO system like layered space time codes, MU-MIMO System and MIMO-OFDM systems

3. UNIT I CAPACITY OF WIRELESS CHANNELS The crowded spectrum, need for high data rate, MIMO systems – Array Gain, Diversity Gain, Data Pipes, Spatial MUX, MIMO System Model. MIMO System Capacity – channel known at the TX, Channel unknown to the TX – capacity of deterministic channels, Random channels and frequency selective channels .

4. W ireless communication system wireless communication system has become an essential part of various types of wireless communication devices, that permits user to communicate even from remote operated areas. There are many devices used for wireless communication like mobiles. Cordless telephones,  Zigbee wirelss technology , GPS, Wi-Fi, satellite television and wireless computer parts. Current wireless phones include 3 and 4G networks, Bluetooth and Wi-Fi technologies.

5. Applications of Wireless Communication Applications of wireless communication involve security systems, television remote control, Wi-Fi, Cell phones,  wireless power transfer , computer interface devices and various wireless  communication based projects .

6. The crowded spectrum The demands on bandwidth and spectral availability are endless. Currently wireless finds its widest expression in fixed and mobile roles.

7. The crowded spectrum cont.. In the fixed role, wireless is used extensively for data transfer, especially from desktop computers and laptops. In the mobile role, wireless networks provide mobility for use from fast vehicles for both voice and data.

8. The crowded spectrum cont.. Consequently wireless designers face an uphill task of limited availability of radio frequency spectrum and complex time varying problems in the wireless channel, such as fading and multipath, as well as meeting the demand for high data rates. Simultaneously, there is an urgent need for better quality of service ( QoS ), compared with that obtainable from DSL and cable.

9. Need for High Data Rates The first mobile communications systems were analog and are today referred to as systems of the first generation. In the beginning of the 1990s, the first digital systems emerged, denoted as second generation (2G) systems which operated in the 900 MHz or the 1,800-MHz band and supported data rates up to 22.8 kbit /s.- all countries except USA uses GSM United States- TDMA/136

10. Need for High Data Rates To accomplish higher data rates two add-ons high-speed circuit switched data (HSCSD) The general packet radio service (GPRS), providing data rates up to 38.4 kbit /s and 172.2 kbit /s, respectively.

11. Need for High Data Rates cont.. The demand for yet higher data rates forced the development of a new generation of wireless systems, the so-called third generation (3G). maximum data rate of at least 384 kbit /s for mobile and 2 mbit /s for indoors.

12. Need for High Data Rates cont.. One of the leading technologies for 3G systems is the now well-known universal mobile telephone system (UMTS) [also referred to as wideband code-division multiplex (WCDMA) or UTRA FDD/TDD] UMTS is the natural evolutionary choice for operators of GSM networks, currently representing a customer base of more than 850 million end users in 195 countries and representing over 70% of today’s digital wireless market. UMTS is also a cellular system and operates in the 2-GHz band. Compared with the 2G systems, UMTS is based on a novel technology.

13. Need for High Data Rates cont.. To yield the 3G data rates, an alternative approach was made with the enhanced data rates for GSM evolution ( EDGE) concept. The EDGE system is based on GSM and operates in the same frequency bands. To enhanced data rates, As for GSM, two add-ons were developed for EDGE, namely enhanced circuit switched data (ECSD) and the enhanced general packet radio service (EGPRS). The maximum data rate of the EDGE system is 473.6 kbit /s, which is accomplished by means of EGPRS.