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General specification of a time-domain multipath channel. More...

#include <itpp/comm/channel.h>

Public Member Functions
	Channel_Specification (const vec &avg_power_dB="0", const vec &delay_prof="0")
	Default constructor (power profile in dB, delay profile in seconds)

	Channel_Specification (const CHANNEL_PROFILE profile)
	Initialize with predetermined channel profile.

virtual	~Channel_Specification ()
	Destructor.

void	set_channel_profile (const vec &avg_power_dB, const vec &delay_prof)
	Set both average power profile in dB and power delay profile in seconds.

void	set_channel_profile (const CHANNEL_PROFILE profile)
	Set channel profile to a predetermined profile.

void	set_doppler_spectrum (DOPPLER_SPECTRUM *tap_spectrum)
	Set doppler spectrum for each tap in the channel profile.

void	set_doppler_spectrum (int tap_number, DOPPLER_SPECTRUM tap_spectrum)
	Set doppler spectrum for tap tap_number in the channel profile.

void	set_LOS (int tap_number, double relative_power, double relative_doppler=0.7)
	Set LOS (Rice) components for tap tap_number.

void	set_LOS (const vec &relative_power, const vec &relative_doppler="")
	Set LOS (Rice) components for all taps.

void	get_channel_profile (vec &avg_power_dB, vec &delay_prof) const
	Get both average power profile in dB and power delay profile in seconds.

vec	get_avg_power_dB () const
	Return power profile in dB.

vec	get_delay_prof () const
	Return delay profile in seconds.

Array< DOPPLER_SPECTRUM >	get_doppler_spectrum () const
	Get doppler spectrum for tap index.

DOPPLER_SPECTRUM	get_doppler_spectrum (int index) const
	Get doppler spectrum for tap index.

vec	get_LOS_power () const
	Get relative power (Rice factor) for each tap.

vec	get_LOS_doppler () const
	Get relative Doppler for each tap.

double	get_LOS_power (int tap_number) const
	Get relative power (Rice factor) for tap tap_number.

double	get_LOS_doppler (int tap_number) const
	Get relative Doppler for tap tap_number.

int	taps () const
	Return the number of channel taps.

double	calc_mean_excess_delay () const
	Calculate mean excess delay in samples.

double	calc_rms_delay_spread () const
	Calculate RMS delay spread in samples.

Protected Attributes
vec	a_prof_dB
	Power profile in dB.

vec	d_prof
	Delay profile in seconds.

Array< DOPPLER_SPECTRUM >	tap_doppler_spectrum
	Doppler spectrum for each tap.

int	N_taps
	Number of taps.

vec	los_power
	Relative power for each Rice component.

vec	los_dopp
	Relative Rice Doppler for each Rice component.

Detailed Description

General specification of a time-domain multipath channel.

Author: Tony Ottosson and Adam Piatyszek

This class does NOT generate any channel values. It is only used to specify the channel model. To generate channel coefficients use the Tapped-Delay Line (TDL) class TDL_Channel.

A time invariant (or at least wide-sense stationary) channel have an impulse response that can be modeled as:

$h(t) = \sum_{k=0}^{N_\mathrm{taps}-1} a_k \exp (-j \theta_k) \delta(t-\tau_k),$

where $N_{taps}$ is the number of channel taps, $ a_k $ is the average amplitude at delay $\tau_k$ , and $\theta_k$ is the channel phase of the $k^{th}$ channel tap. The average power profile, and the delay profiles are defined as:

$\mathbf{a} = [a_0, a_1, \ldots, a_{N_\mathrm{taps}-1}]$

and

$\mathbf{\tau} = [\tau_0, \tau_1, \ldots, \tau_{N_\mathrm{taps}-1}],$

respectively. We assume without loss of generality that $\tau_0 = 0$ and $\tau_0 < \tau_1 < \ldots < \tau_{N_\mathrm{taps}-1}$ .

To initialize the class the following parameters should be defined:

avg_power_dB Average power profile $\mathbf{a}$ , given in dB
delay_profile Delay profile $\mathbf{\tau}$ , given in seconds. The delay profile should be sorted (increasing delay) and the first delay has to be 0.

Optionally one can define LOS parameters: relative_power and relative_doppler, and additionally the kind of Doppler spectrum for each tap.

It is also possible to specify a predefined channel model. The implemented ones are as follows:

ITU Channel models:
- ITU_Vehicular_A, 6-tap channel
- ITU_Vehicular_B, 6-tap channel
- ITU_Pedestrian_A, 4-tap channel
- ITU_Pedestrian_B, 6-tap channel
COST 207 Channel models (see [Pat02] pp. 259-266):
- COST207_RA, Rural area, 4-tap channel
- COST207_RA6, Rural area, 6-tap channel
- COST207_TU, Typical urban, 6-tap channel
- COST207_TU6alt, Typical urban, alternative 6-tap channel
- COST207_TU12, Typical urban, 12-tap channel
- COST207_TU12alt, Typical urban, alternative 12-tap channel
- COST207_BU, Bad urban, 6-tap channel
- COST207_BU6alt, Bad urban, alternative 6-tap channel
- COST207_BU12, Bad urban, 12-tap channel
- COST207_BU12alt, Bad urban, alternative 12-tap channel
- COST207_HT, Hilly terrain, 6-tap channel
- COST207_HT6alt, Hilly terrain, alternative 6-tap channel
- COST207_HT12, Hilly terrain, 12-tap channel
- COST207_HT12alt, Hilly terrain, alternative 12-tap channel
COST 259 Channel models (see [3GPP_TR_25.943]):
- COST259_TUx, Typical urban, 20-tap channel
- COST259_RAx, Rural ara, 10-tap channel
- COST259_HTx, Hilly terrain, 20-tap channel

References:

[Pat02] Matthias Patzold, Mobile fading channels, Wiley, 2002.
[3GPP_TR_25.943] Technical Specification Group Radio Access Networs; Deployment aspects. Version 5.1.0 (2002-06).

Definition at line 691 of file channel.h.

The documentation for this class was generated from the following files:

itpp/comm/channel.h
itpp/comm/channel.cpp

Public Member Functions

Protected Attributes

Detailed Description