bling Code Block Concatenation Code Block Segmentation Scrambling De-Modulation CRC validation Modulation Layer De-Mapping Layer Mapping Channel Estimate, Equalize Precoding Resource Element De-Map interface Forward Error Correction eCPRI encapsulation eCPRI decapsulation Forward Error Correction Rate Matching Rate De-Matching Ethernet MAC Timing/1588 De-Scrambling De-Modulation Offload/FPGA To RU FIGURE 4-9 Typical server PCle/offload scenario for eCPRI and forward error correction. PCIe accelerator boards form factors are characterized by physical dimensions and power draw: Length. Full-length (long) cards can be up to 312 mm and half-length (short) cards are up to 175 mm. Height. A full-height bracket is 111 mm versus a low-profile bracket of 69 mm. Width. A dual-width PCIe card requires access to a second exhaust slot on the back even though it does not need to plug into two PCIe connectors. Power. Power can be supplied with power through the motherboard for <75 W DC power consumption. If more power is required, an auxiliary power cable needs to be plugged in from the power supply. Typical maximum power is 300 W with an additional 225 W delivered from this auxiliary set of connectors. Optimized hardware Server-based solution save time and effort associated with hardware development but are generic in nature which implies that they are not optimized for the bulk of the use-cases-it is unlikely that the combination of compute horse power, IO and power/cost targets are met. So, we end up with a custom hardware design that is either sourced from an Original Device Manufacturer (ODM) that designs and produces the device under the name of the Original Equipment Manufacturer (OEM) or built in-house (by the OEM). Chapter 4 Hardware architecture choices Software/Server DL From MAC UL To MAC eCPRI encapsulation eCPRI decapsulation Ethernet MAC interface CRC Attachment Code Block Concatenation Code Block Segmentation CRC validation Forward Error Correction Forward Error Correction Rate Matching Rate De-Matching eCPRI en