Delay Channels#

Delay channels offer a simple interface to modeling spatial propagation delays of signals in a network of distributed Devices and investigate the delay’s impact on interference and synchronization. They, by design, do not model any fading effects but do consider signal attenuation according to Frii’s transmission formula.

classDiagram class DelayChannelBase { <<Abstract>> +realize() +propagate() } class DelayChannelRealization { <<Abstract>> +propagate() } class RandomDelayChannel { +realize() +propagate() } class RandomDelayChannelRealization { +propagate() } class SpatialDelayChannel { +realize() +propagate() } class SpatialDelayChannelRealization { +propagate() } DelayChannelBase o-- DelayChannelRealization : realize() RandomDelayChannel o-- RandomDelayChannelRealization : realize() SpatialDelayChannel o-- SpatialDelayChannelRealization : realize() RandomDelayChannel --|> DelayChannelBase SpatialDelayChannel --|> DelayChannelBase RandomDelayChannelRealization --|> DelayChannelRealization SpatialDelayChannelRealization --|> DelayChannelRealization click DelayChannelBase href "channel.delay.DelayChannelBase.html" click DelayChannelRealization href "channel.delay.DelayChannelRealization.html" click RandomDelayChannel href "channel.delay.RandomDelayChannel.html" click RandomDelayChannelRealization href "channel.delay.RandomDelayChannelRealization.html" click SpatialDelayChannel href "channel.delay.SpatialDelayChannel.html" click SpatialDelayChannelRealization href "channel.delay.SpatialDelayChannelRealization.html"

Currently, two types of DelayChannels are implemented: RandomDelayChannels and SpatialDelayChannels. Both generate their own type of DelayChannelRealization, namely RandomDelayChannelRealizations and SpatialDelayChannelRealizations, respectively. In general, the delay channel’s impulse response between two devices \(\alpha\) and \(\beta\) featuring \(N^{(\alpha)}\) and \(N^{(\beta)}\) antennas, respectively, is given by

\[\mathbf{H}(t,\tau) = \frac{1}{4\pi f_\mathrm{c}^{(\alpha)}\overline{\tau}} \mathbf{A}^{(\alpha,\beta)} \delta(\tau - \overline{\tau})\]

and depends on the assumed propagation delay \(\overline{\tau}\), the transmitting device’s carrier frequency \(f_\mathrm{c}^{(\alpha)}\) and the antenna array response \(\mathbf{A}^{(\alpha,\beta)}\). The two implementations differ in the way they generate delay \(\overline{\tau}\) and antenna array response \(\mathbf{A}^{(\alpha,\beta)}\).