Hardware Choices For SDR

Standard-cell Integrated Circuits (ICs) are designed in the following conceptual stages, although these stages overlap significantly in practice.
These steps, implemented with a level of skill common in the industry, almost always produce a final device that correctly implements the original design, unless flaws are later introduced by the physical fabrication process.

A team of design engineers starts with a non-formal understanding of the required functions for a new ASIC, usually derived from Requirements analysis.
The design team constructs a description of an ASIC to achieve these goals using an HDL. This process is analogous to writing a computer program in a high-level language. This is usually called the RTL (Register transfer level) design.
Suitability for purpose is verified by simulation. A virtual system created in software, using a tool such as Virtutech's Simics, can simulate the performance of ASICs at speeds up to billions of simulated instructions per second.
A logic synthesis tool, such as Design Compiler, transforms the RTL design into a large collection of lower-level constructs called standard cells. These constructs are taken from a standard-cell library consisting of pre-characterized collections of gates (such as 2 input nor, 2 input nand, inverters, etc.). The standard cells are typically specific to the planned manufacturer of the ASIC. The resulting collection of standard cells, plus the needed electrical connections between them, is called a gate-level netlist.
The gate-level netlist is next processed by a placement tool which places the standard cells onto a region representing the final ASIC. It attempts to find a placement of the standard cells, subject to a variety of specified constraints. Sometimes advanced techniques such as simulated annealing are used to optimize placement.
The routing tool takes the physical placement of the standard cells and uses the netlist to create the electrical connections between them. Since the search space is large, this process will produce a “sufficient” rather than “globally-optimal” solution. The output is a set of photomasks enabling a Semiconductor Fabrication to produce physical ICs.
Close estimates of final delays, parasitic resistances and capacitances, and power consumptions can then be made. In the case of a digital circuit, this will then be further mapped into delay information. These estimates are used in a final round of testing. This testing demonstrates that the device will function correctly over all extremes of the process, voltage and temperature. When this testing is complete the photomask information is released for chip fabrication.

The significant difference is that Standard Cell design uses the manufacturer's cell libraries that have been used in potentially hundreds of other design implementations and therefore are of much lower risk than full custom design. Standard Cells produce a design density that is cost effective, and they can also integrate IP cores and SRAM (Static Random Access Memory) effectively, unlike Gate-Arrays.