| 摘要 |
PURPOSE: An apparatus for transforming AAL2 type ATM cell into AAL2 ATM cell is provided to allow IMT-2000 base station controller to transmit audio data in the form of variable bit rate through AAL2 ATM cell by realizing an FPGA equipment capable of extracting the audio data from the AAL2 ATM cell to transform the same into AAL2 ATM cell. CONSTITUTION: A UTOPIA(Universal Test and Operations Physical Interface for ATM) interface(100) stores AAL2 ATM cell transmitted from a base station through E1-class line in a memory. A VCI(Virtual Channel Identifier) extracting unit(110) extracts a VCI of 2-bit among the ATM cells from the UTOPIA interface(100). A CPS(Common Part Sublayer) packet extracting unit(120) extracts a variable CPS packet from the ATM cells of the VCI extracting unit(10). A CAM(Content-Addressable Memory)(140) a CID in a CPS packet and a VCI in an ATM cell header. A CAM interface(130) transmits to the CAM(140) the VCI and CID extracted from the VCI extracting unit(110) and the CPS packet extracting unit(120), respectively. An SRAM(150) outputs a ATM cell header according to an address outputted from the CAM(140). An ATM cell header generating unit(160) generates AAL2 ATM cell header according to the ATM cell header from the SRAM(150). An AAL2 ATM cell generating unit(170) creates AAL2 ATM cell based on the cell header from the unit(160) and the CPS packet from the unit(120). A multiplexing interface(180) interfaces with a multiplexer on an ATM switch.
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