![]() ![]() #Bandwidth definition computer licenseLTE-M-U supports the 2.4 GHz license exempt frequency band, defined by the frequency range 2400–2483.5 MHz. MFA consequently concluded that the 20-dB bandwidth of an LTE-M-U narrowband should be within 1.8 MHz. The 20-dB bandwidth definition is more stringent than the 3GPP and ETSI occupied bandwidth requirement. This corresponds to the bandwidth where the signal emissions are attenuated by 20 dB relative the power measured in the center of the carrier. The FCC regulations defines the channel bandwidth by its 20-dB bandwidth requirement. An LTE-M-U narrowband of 6 PRBs have a 1.4 MHz channel bandwidth according to this definition which is reused by ETSI. In 3GPP the channel bandwidth is defined as the occupied bandwidth of a modulated waveform which corresponds to the frequency range containing 99% of the total power of the modulated signal. Gustav Wikström, in Cellular Internet of Things (Second Edition), 2020 15.2.2.1.1 Channel raster Compared to the system target of 96 Tbit/s, this is seen to be well below a quarter of the target bandwidth with very optimistic assumptions. This rough analysis, coupled with the above line rate target, caps the off-chip electrical bandwidth at 20 Tbit/s bidirectional (10 Tbit/s each way). Since off-chip electrical channels must be differential at high speed for signal integrity concerns, this yields a rough assumption of 2000 electrical channels. Of the remaining 8000 pins, it is further assumed that half of the total signal pins may be used for the memory interface. Assuming a current limit of 100 mA per pin in a fine pin-pitch package, the 100 A required for a 100 W processor running at 1 V consumes 2000 pins. From this limit, it is possible to estimate the total available channel count by first eliminating the required power supply pins. Considering that current microprocessor packages in high volume products have been limited to roughly 4000 pins and slowly growing, this estimate appears to be an optimistic upper bound. As a result, a yield-limited 1 cm 2 die is limited to approximately 10,000 pins to be connected in a $100 package. This density has been supported by low-cost packaging technology at approximately $0.01 per pin. The dominant packaging technology for CPUs, flip-chip bonding, will enable scaling-limited electrical connections at a pitch of approximately 100 μm in a 2D array. The off-chip electrical channel density currently faces hard packaging limits that are the largest impediment toward increasing the off-chip bandwidth of processors. The fixed channel bandwidth is expected to be more than offset by a substantial increase in parallelism enabled by optics. Vladimir Stojanović, in Optical Fiber Telecommunications (Sixth Edition), 2013 12.1.2.2 Channel density ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |