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The Wi-Fi Alliance is a nonprofit international association formed in 1999 to certify interoperability of wireless Local Area Network products based on the IEEE 802.11 specification. Currently the Wi-Fi Alliance has 207 member companies from around the world, and 611 products have received Wi-Fi certification since certification began in March of 2000.

TV06B101J-HF_Datasheet PDF

The Wi-Fi Alliance is a nonprofit international association formed in 1999 to certify interoperability of wireless Local Area Network products based on the IEEE 802.11 specification. Currently the Wi-Fi Alliance has 207 member companies from around the world, and 611 products have received Wi-Fi certification since certification began in March of 2000.

Another option would be to keep the existing memory model function and messaging in the traditional HDL but incorporate an already available C-based memory core to handle the new advanced capabilities. The advantages here are that the existing HDL templates are kept and just slightly modified to include the new C-based core. Minimal time and experience is required to do this. All existing error, warning and notes messages are kept the same.

The Infineon Technologies embedded memory group based in Sophia, France, faced these issues. Their existing models were written in traditional HDL's. Users of these embedded memories requested support for these types of testbench capabilities. Infineon required a solution that met the following requirements: the model had to be supported internally; it had to have a reduced memory footprint over HDL models; it needed testbench-to-memory debug capabilities and it had to fit into their existing design flow.

TV06B101J-HF_Datasheet PDF

Infineon's chose to incorporate an already available C-based memory core to achieve this. They converted their existing HDL embedded memory models to use the Synopsys DesignWare C-based memory core, known as memcore. This simple inclusion provides support for dynamic system memory allocation, which reduces the memory footprint and provides advanced testbench-to-memory debug capabilities.

In simplistic terms, memcore replaces both the HDL memory array declarations and the reading and writing from these arrays. The models' function is kept in the HDL and all error, warnings and notes messages are still generated from the HDL. The only real change is that the data for a read or write is stored in the C-based memcore rather than in an array in HDL code.

Easy fit, end user issues

TV06B101J-HF_Datasheet PDF

Infineon's engineers chose this solution based on the ease in which their HDL template could be modified to include the C-based core. It fit into their existing design flow without any additional changes. In half a day, the team was able to update and validate their embedded memory compilers and resulting models. The changes needed to update existing models were minor, but the added functionalities for end users (ASIC designers) were significant. Below are some examples:

Example: HDL declarations for a 4M X 32 bit memory:

TV06B101J-HF_Datasheet PDF

Verilog

reg[31:0] mem[0:4095];

Multi-path energy collection is also a fundamental issue because it determines the range of a communication system. It has been shown that with a single RF receive chain, the pulse-based system cannot achieve the required 10-m range. However, it is possible to finally achieve the necessary range with the multi-band approach, but it usually comes at the expense of increases in receiver complexity (i.e. multiple RF receive chains), power consumption, analog die size and increased design time.

On the other hand, multi-carrier, multi-band systems use orthogonal frequency division multiplexing (OFDM) techniques to transmit the information on each of the sub-bands. OFDM has several nice properties, including high spectral efficiency, inherent resilience to RF interference, robustness to multi-path, and the ability to efficiently capture multi-path energy. It is also well understood and has been proven in other commercial technologies (ex. IEEE 802.11a/g).

The main advantages are that it is easier to collect multi-path energy using a single RF chain, relaxed switching times, insensitivity to group delay variations, and ability to deal with narrowband interference at the receiver without having to sacrifice sub-bands or data rate. The only drawback of this type of system is that the transmitter is slightly more complex because it requires an IFFT and the peak-to-average ratio may be slightly higher than that of the pulse-based multi-band approaches.

Diving into Multiband OFDM Now that we've taken a brief look at the different multi-band approaches available to designers, let's examine the OFDM-based multiband approach further.

Given the frequency band from 3.1 GHz to 4.8 GHz and the FCC requirement that UWB signals have to be at least 500 MHz, only three sub-bands can be used in the initial deployment of multi-band OFDM systems. Figure 1 illustrates one way to allocate the three sub-bands with the given frequency allocation.

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