STRLCPY/wirelesscomm

Added BF lab
Sundeep Rangan committed 3 years ago

092082d4

1 parent 6847abd9

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readme.md

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78	78		* Lecture: [[PDF]](./lectures/Unit08_Beamforming.pdf) [[PPT]](./lectures/Unit08_Beamforming.pptx)
79	79		* Demo: Visualizing and simualting arrays [[PDF]](./unit08_bf/demoBF.pdf) [[Matlab Live]](./unit08_bf/demoBF.mlx)
80	80		* Demo: Pattern multiplication and mutual coupling [[PDF]](./unit08_bf/mutualCoupling.pdf) [[Matlab Live]](./unit08_bf/mutualCoupling.mlx)
	81	+	* Lab: Simulating beamforming on a 28 GHz channel [[PDF]](./unit08_bf/labPartial/labBF.pdf) [[Matlab Live]](./unit08_bf/labPartial/labBF.pdf)
81	82		* Problems: [[PDF]](./unit08_bf/prob/prob_bf.pdf) [[Latex]](./unit08_bf/prob/prob_bf.tex)
82	83		* Unit 9. Beam Tracking and Directional Estimation
83	84		* Unit 10. Introduction to MIMO
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unit08_bf/labPartial/ArrayPlatform.m

1	+	classdef ArrayPlatform < matlab.System
2	+	% ArrayWithAxes. Class containing an antenna array and axes.
3	+	properties
4	+
5	+	fc = 28e9; % Carrier frequency
6	+
7	+	% Element within each array.
8	+	elem = [];
9	+
10	+	% Gridded interpolant object for the element gain in linear scale
11	+	elemGainInterp = [];
12	+
13	+	% Antenna array.
14	+	arr = [];
15	+
16	+	% Steering vector object
17	+	svObj = [];
18	+
19	+	% Azimuth and elevation angle of the element peak directivity
20	+	axesAz = 0;
21	+	axesEl = 0;
22	+
23	+	% Axes of the element local coordinate frame of reference
24	+	axesLoc = eye(3);
25	+
26	+	% Velocity vector in 3D in m/s
27	+	vel = zeros(1,3);
28	+
29	+	% Position in m
30	+	pos = zeros(1,3);
31	+
32	+	% Normalization matrix
33	+	Qinv = [];
34	+	end
35	+
36	+	methods
37	+	function obj = ArrayPlatform(varargin)
38	+	% Constructor
39	+
40	+	% Set key-value pair arguments
41	+	if nargin >= 1
42	+	obj.set(varargin{:});
43	+	end
44	+	end
45	+
46	+
47	+
48	+	function computeNormMatrix(obj)
49	+	% The method performs two key tasks:
50	+	% * Measures the element pattern and creates a gridded
51	+	% interpolant object to interpolate the values at other
52	+	% angles
53	+	% * Compute the normalization matrix to account for mutual
54	+	% coupling
55	+
56	+	% TODO: Get the pattern for the element using the elem.pattern
57	+	% method
58	+	% [elemGain,az,el] = obj.elem.pattern(...);
59	+
60	+
61	+	% TODO: Create the gridded interpolant object
62	+	% for element gain
63	+	% obj.elemGainInterp = griddedInterpolant(...);
64	+
65	+
66	+	% Get a vector of values with the elements az(i) and el(j).
67	+	[azMat, elMat] = meshgrid(az, el);
68	+	azVal = azMat(:);
69	+	elVal = elMat(:);
70	+	elemGainVal = elemGain(:);
71	+
72	+	% TODO: Create a steering vector object with the array
73	+	% obj.svObj = phased.SteeringVector(...);
74	+
75	+
76	+	% TODO: Get the steering vectors
77	+	% Sv0 = obj.svObj(...);
78	+
79	+
80	+	% TODO: Compute un-normalized spatial signature
81	+	% by multiplying the steering vectors with the element gain
82	+	% SvNoNorm = ...
83	+
84	+
85	+	% TODO: Compute the normalization matrix by integrating the
86	+	% un-normalized steering vectors
87	+	% Q = ...
88	+
89	+	% Ensure matrix is Hermitian
90	+	Q = (Q+Q')/2;
91	+
92	+	% TODO: Save the inverse matrix square root of Q
93	+	% obj.Qinv = ...
94	+
95	+	end
96	+
97	+	function alignAxes(obj,az,el)
98	+	% Aligns the axes to given az and el angles
99	+
100	+	% Set the axesAz and axesEl to az and el
101	+	obj.axesAz = az;
102	+	obj.axesEl = el;
103	+
104	+	% Creates axes aligned with az and el
105	+	obj.axesLoc = azelaxes(az,el);
106	+	end
107	+
108	+	function dop = doppler(obj,az,el)
109	+	% Computes the Doppler shift of a set of paths
110	+	% The angles of the paths are given as (az,el) pairs
111	+	% in the global frame of reference.
112	+
113	+	% Finds unit vectors in the direction of each path
114	+	npath = length(el);
115	+	[u1,u2,u3] = sph2cart(deg2rad(az),deg2rad(el),ones(1,npath));
116	+	u = [u1; u2; u3];
117	+
118	+	% Compute the Doppler shift of each path via an inner product
119	+	% of the path direction and velocity vector.
120	+	vcos = obj.vel*u;
121	+	vc = physconst('lightspeed');
122	+	dop = vcos*obj.fc/vc;
123	+
124	+	end
125	+
126	+	function releaseSV(obj)
127	+	% Creates the steering vector object if it has not yet been
128	+	% created. Otherwise release it. This is needed since the
129	+	% sv object requires that it takes the same number of
130	+	% inputs each time.
131	+	if isempty(obj.svObj)
132	+	obj.svObj = phased.SteeringVector('SensorArray',obj.arr);
133	+	else
134	+	obj.svObj.release();
135	+	end
136	+
137	+	end
138	+
139	+	function n = getNumElements(obj)
140	+	% Gets the number of elements
141	+	n = obj.arr.getNumElements();
142	+
143	+	end
144	+
145	+	function elemPosGlob = getElementPos(obj)
146	+	% Gets the array elements in the global reference frame
147	+
148	+	% Get the element position in the local reference frame
149	+	elemPosLoc = obj.arr.getElementPosition();
150	+
151	+	% Convert to the global reference frame
152	+	elemPosGlob = local2globalcoord(elemPosLoc, 'rr', ...
153	+	zeros(3,1), obj.axesLoc) + reshape(obj.pos,3,1);
154	+	end
155	+
156	+	end
157	+
158	+	methods (Access = protected)
159	+
160	+	function setupImpl(obj)
161	+	% setup: This is called before the first step.
162	+	obj.computeNormMatrix();
163	+
164	+
165	+	end
166	+
167	+	function releaseImpl(obj)
168	+	% release: Called to release the object
169	+	obj.svObj.release();
170	+	end
171	+
172	+	function [Sv, elemGain] = stepImpl(obj, az, el, relSV)
173	+	% Gets normalized steering vectors and element gains for a set of angles
174	+	% The angles az and el should be columns vectors along which
175	+	% the outputs are to be computed.
176	+	% If the relSV == true, then the steering vector object is
177	+	% released. This is needed in case the dimensions of the past
178	+	% call are the different from the past one
179	+
180	+	% Release the SV
181	+	if nargin < 4
182	+	relSV = true;
183	+	end
184	+	if relSV
185	+	obj.releaseSV();
186	+	end
187	+
188	+	% TODO: Convert the global angles (az, el) to local
189	+	% angles (azLoc, elLoc). Use the
190	+	% global2localcoord() method with the 'ss' option.
191	+
192	+
193	+	% TODO: Get the SV in the local coordinates
194	+	% Sv0 = obj.svObj(...)
195	+
196	+
197	+	% TODO: Get the directivity gain of the element from the
198	+	% local angles.
199	+	% elemGain = obj.elem.step(...)
200	+
201	+
202	+	% TODO: Compute the normalized steering vectors
203	+	% Sv = ...
204	+
205	+
206	+
207	+	end
208	+
209	+	end
210	+
211	+
212	+	end
213	+

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unit08_bf/labPartial/FDMIMOChan.m

1	+	classdef FDMIMOChan < matlab.System
2	+	% Frequency-domain MIMO multipath channel
3	+	properties
4	+	% Configuration
5	+	carrierConfig; % Carrier configuration
6	+	waveformConfig; % Waveform parameters
7	+
8	+	% Path parameters
9	+	gain; % Relative path gain in dB
10	+	dly; % Delay of each path in seconds
11	+	aodAz, aodEl; % Angle of departure of each path in degrees
12	+	aoaAz, aoaEl; % Angle of arrival of each path in degrees
13	+
14	+	% Derived path parameters
15	+	fd; % Doppler shift for each path
16	+	gainComplex; % Complex gain of each path
17	+	svTx, svRx; % Steering vectors for each path
18	+	elemGainTx, elemGainRx; % Element gains
19	+
20	+	% Other parmaters
21	+	fc = 28e9; % Carrier freq in Hz
22	+	rxVel = [30,0,0]'; % RX velocity vector in m/s
23	+	txVel = [0,0,0]'; % TX velocity vector in m/s
24	+	Enoise = 0; % Noise energy per sample in dBmJ
25	+
26	+	% Symbol times
27	+	symStart; % symStart(i) = start of symbol i relative to subframe
28	+
29	+	% TX and RX array platforms
30	+	txArrPlatform = [];
31	+	rxArrPlatform = [];
32	+
33	+	end
34	+	methods
35	+	function obj = FDMIMOChan(carrierConfig, varargin)
36	+	% Constructor
37	+
38	+	% Save the carrier configuration
39	+	obj.carrierConfig = carrierConfig;
40	+
41	+	% Set parameters from constructor arguments
42	+	if nargin >= 1
43	+	obj.set(varargin{:});
44	+	end
45	+
46	+	% Check all the required fields are specified
47	+	fields = {'txArrPlatform', 'rxArrPlatform', 'gain', 'dly', ...
48	+	'aoaAz', 'aodAz', 'aoaEl', 'aoaAz' };
49	+	nfields = length(fields);
50	+	for i = 1:nfields
51	+	fstr = fields{i};
52	+	if isempty(obj.(fstr))
53	+	e = MException('FDMIMOChan:missingParam', ...
54	+	'Parameter %s not speficied', fstr);
55	+	throw(e);
56	+	end
57	+	end
58	+
59	+	% Complex gain for each path using a random initial phase
60	+	% The gains are normalized to an average of one
61	+	npath = length(obj.gain);
62	+	phase = 2pirand(npath, 1);
63	+	obj.gainComplex = db2mag(obj.gain).exp(1iphase);
64	+
65	+	% Symbol times relative to the start of the subframe
66	+	obj.waveformConfig = nrOFDMInfo(obj.carrierConfig);
67	+	nsym = obj.waveformConfig.SymbolLengths;
68	+	obj.symStart = nsym/obj.waveformConfig.SampleRate;
69	+	obj.symStart = cumsum([0 obj.symStart]');
70	+
71	+	% Get Doppler shift for RX
72	+	vc = physconst('Lightspeed');
73	+	[ux, uy, uz] = sph2cart(deg2rad(obj.aoaAz), deg2rad(obj.aoaEl), 1);
74	+	obj.fd = [ux uy uz]obj.rxVelobj.fc/vc;
75	+
76	+	% Get Doppler shift for TX
77	+	[ux, uy, uz] = sph2cart(deg2rad(obj.aodAz), deg2rad(obj.aodEl), 1);
78	+	obj.fd = obj.fd + [ux uy uz]obj.txVelobj.fc/vc;
79	+	end
80	+
81	+	function computePathSV(obj)
82	+	% Computes the element gains and steering vectors of each path
83	+
84	+	% Call the array platform objects to get the steering vectors
85	+	% and element gains
86	+	[obj.svTx, obj.elemGainTx] = ...
87	+	obj.txArrPlatform.step(obj.aodAz, obj.aodEl);
88	+	[obj.svRx, obj.elemGainRx] = ...
89	+	obj.rxArrPlatform.step(obj.aoaAz, obj.aoaEl);
90	+
91	+	end
92	+
93	+
94	+	end
95	+	methods (Access = protected)
96	+
97	+
98	+	function [chanGrid, noiseVar] = stepImpl(obj, frameNum, slotNum)
99	+	% Applies a frequency domain channel and noise
100	+	%
101	+	% Parameters
102	+	% ----------
103	+	% frameNum: The index of the frame (1 frame = 10ms)
104	+	% slotNum: The index of the slot in the frame
105	+	% This should be 0,...,waveformConfig.SlotsPerFrame
106	+	%
107	+	% Outputs
108	+	% -------
109	+	% chanGrid: Grid of the channel values
110	+	% noiseVar: Noise variance
111	+
112	+	% Compute the steering vectors and element gains
113	+	obj.computePathSV();
114	+
115	+	% Get the number of TX and RX elements
116	+	ntx = obj.txArrPlatform.getNumElements();
117	+	nrx = obj.rxArrPlatform.getNumElements();
118	+
119	+	% Get the number of sub-carriers
120	+	nscPerRB = 12;
121	+	nsc = obj.carrierConfig.NSizeGrid * nscPerRB;
122	+	nsym = obj.carrierConfig.SymbolsPerSlot;
123	+
124	+	% Compute the frequency of each carrier
125	+	f = (0:nsc-1)'obj.carrierConfig.SubcarrierSpacing1e3;
126	+
127	+	% Compute slot in sub-frame and sub-frame index
128	+	sfNum = floor(slotNum / obj.waveformConfig.SlotsPerSubframe);
129	+	slotNum1 = mod(slotNum, obj.waveformConfig.SlotsPerSubframe);
130	+
131	+	% Compute the time for each symbol
132	+	framePeriod = 0.01;
133	+	sfPeriod = 1e-3;
134	+	t = frameNumframePeriod + sfPeriodsfNum + ...
135	+	obj.symStart(slotNum1+1:slotNum1+nsym);
136	+
137	+	% Initialize the channel grid to zero
138	+	chanGrid = zeros(nrx, ntx, nsc, nsym);
139	+	npath = length(obj.gain);
140	+
141	+
142	+	% TODO: Set the channel:
143	+	%
144	+	% chanGrid(j,k,n,t) = MIMO channel matrix from
145	+	% RX antenna j, TX antenna k, sub-carrier n,
146	+	% symbol t.
147	+	%
148	+	% This should be a sum of the paths
149	+	%
150	+	% chanGrid(j,k,:,:)
151	+	% = \sum_i exp(1iphase)svRx(j,i)*svTx(k,i)
152	+	%
153	+	% where
154	+	%
155	+	% phase = 2pi(fobj.dly(i) + t'obj.fd(i));
156	+
157	+
158	+	% Compute noise variance
159	+	noiseVar = db2pow(obj.Enoise);
160	+
161	+
162	+	end
163	+
164	+	end
165	+	end
166	+
167	+

unit08_bf/labPartial/labBF.mlx

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unit08_bf/labPartial/labBF.pdf

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unit08_bf/mutualCoupling.mlx

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Added BF lab