rl_ofdm_calib.m File Reference

Functions
Number of CP samples to use in	FFT (on average) %% Define the preamble % LTS for fine CFO and channel estimation lts_f
	sched_id (REF_ANT)
	preamble (nid, start_index+1:start_index+N_SYM_SAMP)
	preamble (REF_ANT, start_index+1:start_index+N_SYM_SAMP)
initialize BS node_bs	sdrsync ()
synchronize delays only for BS node_bs	sdrrxsetup ()
configure the N_ZPAD_PRE	preamble (i, :) zeros(1
node_bs	sdrtx_single (tx_data, i)
Burn data to the UE RAM end node_bs	sdr_activate_rx ()
end	payload_rx (ibs, :)
	if (ibs==REF_ANT) rx_fft_ref(sid
id	start_index: (id N_SC)
else	rx_fft (sid, :)
end node_bs	sdr_close ()
	figure (cf)
	plot (-32:1:31, abs(cal_mat(i, :)))
	axis ([-40 40 0 5]) grid on
	title ('Calibration MAGNITUDE')
	plot (-32:1:31, angle(cal_mat(i, :)))
	title ('Calibration ANGLE')

Variables
	Author (s)[version, executable, isloaded] = pyversion
if ~isloaded pyversion usr bin python py print() %weird bug where py isn 't loaded in an external script end % Params Enable writing plots to PNG Iris	params
	TX_FRQ = 2.5e9
	RX_FRQ = TX_FRQ
	TX_GN = 70
	RX_GN = 50
	SMPL_RT = 5e6
	N_FRM = 1
	bs_ids = string.empty()
	bs_sched = string.empty()
Waveform params OFDM params	SC_IND_PILOTS = [8 22 44 58]
Pilot subcarrier indices	SC_IND_DATA = [2:7 9:21 23:27 39:43 45:57 59:64]
Data subcarrier indices	SC_IND_DATA_PILOT = [2:27 39:64]'
	N_SC = 64
Number of subcarriers	CP_LEN = 16
Cyclic prefix length	N_SYM_SAMP = N_SC + CP_LEN
Number of samples that will go over the air	N_ZPAD_PRE = 100
Number of OFDM symbols for	burst
Number of OFDM symbols for it needs to be less than Rx processing params	FFT_OFFSET = 16
	lts_t = ifft(lts_f, 64)
time domain Init Iris nodes Set up the Iris experiment Create BS Hub and UE objects	Note
else	hub_id = []
All BS	schedule
All BS Ref Schedule	N_BS_NODE = length(bs_ids)
	REF_ANT = floor(N_BS_NODE/2)
	sched_id = ones(1, N_BS_NODE)
	lts = [lts_t(49:64) lts_t]
	N_BS = N_BS_NODE - 1
	DATA_REP = floor(N_OFDM_SYM / N_BS)
	data_len = N_BS * DATA_REP * N_SYM_SAMP
	preamble = zeros(N_BS_NODE, data_len)
for	jp
for	rp
end end	n_samp = N_ZPAD_PRE + data_len + N_ZPAD_POST
	payload_rx = zeros(N_BS_NODE, data_len)
	rx_fft = zeros(N_BS, N_SC)
	rx_fft_ref = zeros(N_BS, N_SC)
	cal_mat = zeros(N_BS, N_SC)
Iris nodes parameters	bs_sdr_params
	node_bs = iris_py(bs_sdr_params, hub_id)
for	i
configure the	BS
configure the N_ZPAD_PRE	N_ZPAD_POST
activate reading	stream [rx_vec_iris, data0_len] = node_bs.sdrrx(n_samp)
read data process received reciprocity pilots	a = 1
	unos = ones(size(conj(lts)))
for	ibs
	v1 = filter(unos, a, abs(rx_vec_iris(ibs, end - DATA_REP * N_SYM_SAMP: end)) .^ 2)
	lts_corr = (abs(v0) .^ 2) ./ v1
normalized correlation position of the last	peak [~, max_idx] = max(abs(lts_corr))
	rx_data_start
	break
for	sid
	start_index = CP_LEN + ((rid - 1) + (sid - 1) * DATA_REP) * N_SYM_SAMP
	__pad2__
	__pad3__
	cf = 0
	clf

Function Documentation

axis()

axis

(

)

FFT()

Number of CP samples to use in FFT

(

on

average

)

figure()

figure

(

cf

)

if()

if

(

ibs

= = REF_ANT

)

payload_rx()

end payload_rx	(	ibs	,
		:
	)

plot() [1/2]

plot	(	-32:1:31	,
		abs(cal_mat(i, :))
	)

plot() [2/2]

plot	(	-32:1:31	,
		angle(cal_mat(i, :))
	)

preamble() [1/3]

configure the N_ZPAD_PRE preamble	(	i	,
		:
	)

preamble() [2/3]

preamble	(	nid	,
		start_index+1:start_index+	N_SYM_SAMP
	)

preamble() [3/3]

preamble	(	REF_ANT	,
		start_index+1:start_index+	N_SYM_SAMP
	)

rx_fft()

else rx_fft	(	sid	,
		:
	)

sched_id()

sched_id

(

REF_ANT

)

sdr_activate_rx()

Burn data to the UE RAM end node_bs sdr_activate_rx

(

)

sdr_close()

end node_bs sdr_close

(

)

sdrrxsetup()

synchronize delays only for BS node_bs sdrrxsetup

(

)

sdrsync()

initialize BS node_bs sdrsync

(

)

sdrtx_single()

node_ue sdrtx_single	(	tx_data	,
		i
	)

start_index:()

id start_index: ( id  N_SC )

staticvirtual

title() [1/2]

title

(

'Calibration ANGLE'

)

title() [2/2]

title

(

'Calibration MAGNITUDE'

)

Variable Documentation

__pad2__

__pad2__

__pad3__

__pad3__

a

read data process received reciprocity pilots a = 1

Author

Author(s)[version, executable, isloaded] = pyversion

break

break

BS

configure the BS

bs_ids

else bs_ids = string.empty()

bs_sched

All BS Ref Schedule bs_sched = string.empty()

bs_sdr_params

Iris nodes parameters bs_sdr_params

Initial value:

= struct(...
    'id', bs_ids, ...
    'n_sdrs', N_BS_NODE, ...
    'txfreq', TX_FRQ, ...
    'rxfreq', RX_FRQ, ...
    'txgain', TX_GN, ...
    'rxgain', RX_GN, ...
    'sample_rate', SMPL_RT, ...
    'n_samp', n_samp, ...          % number of samples per frame time.
    'n_frame', 1, ...
    'tdd_sched', bs_sched, ...     % number of zero-paddes samples
    'n_zpad_samp', N_ZPAD_PRE ...
    )

burst

Number of OFDM symbols for burst

cal_mat

cal_mat = zeros(N_BS, N_SC)

cf

end cf = 0

clf

clf

CP_LEN

Number of subcarriers CP_LEN = 16

data_len

data_len = N_BS * DATA_REP * N_SYM_SAMP

DATA_REP

DATA_REP = floor(N_OFDM_SYM / N_BS)

FFT_OFFSET

Number of OFDM symbols for it needs to be less than Rx processing params FFT_OFFSET = 16

hub_id

else hub_id = []

i

additional pilot as noise for i

Initial value:

=1:N_BS_NODE
    node_bs.set_tddconfig_single(1, bs_sched(sched_id(i)), i)

ibs

for ibs

Initial value:

= 1:N_BS_NODE
    % Correlation through filtering
    v0 = filter(fliplr(conj(preamble(REF_ANT, end - DATA_REP * N_SYM_SAMP: end))), a, rx_vec_iris(ibs, end - DATA_REP * N_SYM_SAMP: end))

jp

for jp

Initial value:

= 1:N_BS
    nid = jp + (jp >= REF_ANT)

lts

lts = [lts_t(49:64) lts_t]

lts_corr

lts_corr = (abs(v0) .^ 2) ./ v1

lts_t

lts_t = ifft(lts_f, 64)

N_BS

N_BS = N_BS_NODE - 1

N_BS_NODE

All BS Ref Schedule N_BS_NODE = length(bs_ids)

N_FRM

N_FRM = 1

n_samp

end end n_samp = N_ZPAD_PRE + data_len + N_ZPAD_POST

N_SC

N_SC = 64

N_SYM_SAMP

Cyclic prefix length N_SYM_SAMP = N_SC + CP_LEN

N_ZPAD_POST

id N_ZPAD_POST

N_ZPAD_PRE

Number of samples that will go over the air N_ZPAD_PRE = 100

node_bs

node_bs = iris_py(bs_sdr_params, hub_id)

Note

time domain Init Iris nodes Set up the Iris experiment Create BS Hub and UE objects Note

params

if ~isloaded pyversion usr bin python py print () %weird bug where py isn't loaded in an external script end % Params Enable writing plots to PNG Iris params

payload_rx

payload_rx = zeros(N_BS_NODE, data_len)

peak

normalized correlation position of the last peak[~, max_idx] = max(abs(lts_corr))

preamble

preamble = zeros(N_BS_NODE, data_len)

REF_ANT

REF_ANT = floor(N_BS_NODE/2)

rp

for rp

Initial value:

= 1:DATA_REP
        start_index = ((rp - 1) + (jp - 1) * DATA_REP) * N_SYM_SAMP

rx_data_start

rx_data_start

Initial value:

= max_idx + (n_samp - DATA_REP * N_SYM_SAMP) - data_len
    if rx_data_start < 0
       display('bad receive!')

rx_fft

rx_fft = zeros(N_BS, N_SC)

rx_fft_ref

rx_fft_ref = zeros(N_BS, N_SC)

RX_FRQ

RX_FRQ = TX_FRQ

RX_GN

RX_GN = 50

SC_IND_DATA

Pilot subcarrier indices SC_IND_DATA = [2:7 9:21 23:27 39:43 45:57 59:64]

SC_IND_DATA_PILOT

Data subcarrier indices SC_IND_DATA_PILOT = [2:27 39:64]'

SC_IND_PILOTS

Waveform params OFDM params SC_IND_PILOTS = [8 22 44 58]

sched_id

sched_id = ones(1, N_BS_NODE)

schedule

All BS schedule

sid

end end end end for sid

Initial value:

= 1:N_BS
        for rid = 1:DATA_REP
            % nid = sid + (sid >= REF_ANT)

SMPL_RT

SMPL_RT = 5e6

start_index

start_index = CP_LEN + ((rid - 1) + (sid - 1) * DATA_REP) * N_SYM_SAMP

stream

activate reading stream[rx_vec_iris, data0_len] = node_bs.sdrrx(n_samp)

TX_FRQ

TX_FRQ = 2.5e9

TX_GN

TX_GN = 70

unos

unos = ones(size(conj(lts)))

v1

v1 = filter(unos, a, abs(rx_vec_iris(ibs, end - DATA_REP * N_SYM_SAMP: end)) .^ 2)