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Multi-Carrier and Spread Spectrum Systems: From OFDM and MC ...

Multi-Carrier and Spread Spectrum Systems: From OFDM and MC ...

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332 Additional Techniques for Capacity <strong>and</strong> Flexibility EnhancementTable 6-3Examples of current wireless communication st<strong>and</strong>ardsMobile communication systemsWireless LAN/WLLCDMA based TDMA based <strong>Multi</strong>-carrier orCDMA basedIS-95/-B: digitalcellular st<strong>and</strong>ardin the USAWCDMA/UMTS :wideb<strong>and</strong> CDMACDMA-2000 :multi-carrierCDMA based onIS-95TD-CDMA: timedivisionsynchronousCDMAGSM : global systemfor mobilecommunicationsPDC : personal digitalcellular systemIS-136 :NorthAmerican TDMAsystemUWC136 : universalwirelesscommunicationsbased on IS-136GPRS : general packetradio serviceEDGE: enhanceddata rate for globalevolutionIEEE. 802.11a/b:WLAN based on<strong>OFDM</strong>/CDMAHIPERMAN :WLLbasedon<strong>OFDM</strong>IEEE 802.16d: WLLbasedon<strong>OFDM</strong>Non-<strong>MC</strong>, non-CDMAbasedDECT : digitalenhanced cordlesstelecommunicationsHIPERACCESS :WLL based onsingle-carrier TDMAIEEE 802.16 :WLLbased onsingle-carrier TDMAChapter 5, the integration of all these existing <strong>and</strong> future st<strong>and</strong>ards in a common platformis one of the major goals of the next generation (4G) of wireless systems.Hence, a fast adaptation/integration of existing systems to emerging new st<strong>and</strong>ardswould be feasible if the 4G system has a generic architecture, while its receiver <strong>and</strong>transmitter parameters are both reconfigurable per software.6.5.1 GeneralA common underst<strong>and</strong>ing of a software-defined radio (SDR) is that of a transceiver, wherethe functions are realized as programs running on suitable processors or re-programmablecomponents [27]. On the hardware, different transmitter/receiver algorithms, whichdescribe transmission st<strong>and</strong>ards, could be executed for corresponding application software.For instance, the software can be specified in such a manner that several st<strong>and</strong>ards can beloaded via parameter configurations. This strategy can offer a seamless change/adaptationof st<strong>and</strong>ards, if necessary.The software-defined radio can be characterized by the following features:– The radio functionality is configured per software.– Different st<strong>and</strong>ards can be executed on the hardware according to the parameter lists.

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