bandwidthperwatt

Bandwidth per watt, abbreviated BPW, is a measure of energy efficiency in communications and information processing. It describes how much data bandwidth can be obtained for every watt of power consumed, and is commonly expressed as bits per second per watt (bps/W) for a given system.

Calculation and scope: BPW is defined as the data rate (throughput) divided by power consumption. The data rate is the sustained throughput under representative workloads, and power is the real or average electrical power draw of the device, subsystem, or component. BPW can be reported at different scopes, such as a wireless transceiver, a base station, a data-center server, or an embedded chip, and may include or exclude auxiliary power such as cooling depending on the testing protocol.

Applications: BPW is used to compare energy efficiency across technologies and configurations, guiding design decisions for modulation, coding, hardware architecture, and power management. It is relevant in wireless networks, optical communications, data centers, and battery-powered devices.

Measurement and interpretation: BPW values depend heavily on workload, channel conditions, hardware architecture, and testing methodology. Without standard conditions, comparisons can be misleading. Related metrics such as bits per joule, throughput per watt, and energy-delay product are often used to provide a fuller picture of performance-per-energy.

Limitations: BPW should be interpreted in context of latency, quality of service, and total energy for complete tasks. A high BPW may come at the expense of increased latency or reduced reliability if not considered together with other requirements.

See also: energy efficiency, bits per joule, throughput, COP.