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|
(define-module (simulation)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-69)
#:use-module (ice-9 atomic)
#:use-module (ice-9 match)
#:use-module (fibers)
#:use-module (fibers channels)
#:use-module (fibers timers))
(define RX1 1) ; s (has to be between 1-15s)
(define RX2 (1+ RX1)) ; s
(define RECEIVE_DELAY1 1) ; s
(define RECEIVE_DELAY2 (1+ RECEIVE_DELAY1)) ; s
;; From RP002 (Regional Parameters):
;; MAC commands exist in the LoRaWAN® specification to change the value of
;; RECEIVE_DELAY1 (using RXTimingSetupReq, RXTimingSetupAns) as well as
;; ADR_ACK_LIMIT and ADR_ACK_DELAY (using ADRParamSetupReq, ADRParamSetupAns).
;; Also, RXTimingSettings are transmitted to the end device along with the
;; JOIN_ACCEPT message in OTAA mode.
;; TODO: put a time limit as a parameter
(define-syntax-rule (forever exp ...)
(let loop ()
(begin exp ...)
(loop)))
(define (ll f . data)
(let ((now (gettimeofday)))
(format #t "~a~a - ~?~%" (car now) (cdr now) f data)))
;; type can be:
;; 'start
;; 'end
(define-record-type <event>
(make-event type data)
event?
(type event-type)
(data event-data))
;; body can be:
;; 'unconfirmed-data (uplink)
;; 'confirmed-data (uplink)
;; 'ack (downlink)
(define-record-type <packet>
(make-packet id device-id channel-n uplink? body)
packet?
(id packet-id)
(device-id packet-device-id)
(channel-n packet-channel-n)
(uplink? packet-uplink?) ;; TODO: we could check this
(body packet-body))
(define-record-type <device>
(make-device channel thunk)
device?
(channel device-channel)
(thunk device-thunk))
(define (rand-time)
(random 2))
(define (make-class-a id initial-channel upstream-chn downstream-chn)
;; Make all atomic
(define channel initial-channel)
;; TODO: Unhardcode me
(define time-on-air 0.01)
(define to-confirm (make-atomic-box #f))
;; Handle the receive windows
(define listening? (make-atomic-box #f))
(define (start-listening!)
(ll "Device ~a started listening" id)
(atomic-box-set! listening? #t))
(define (stop-listening!)
(ll "Device ~a stopped listening" id)
(atomic-box-set! listening? #f))
(define (im-listening?)
(atomic-box-ref listening?))
(define (confirm packet-id)
(when (eq? packet-id (atomic-box-compare-and-swap! to-confirm packet-id #f))
(spawn-fiber
(lambda () "confirm confirmation packet"))))
(define (upstream)
(define current-packet 0)
(forever
(when (eq? #f (atomic-box-ref to-confirm))
(ll "Device ~a waiting for data" id)
(sleep (rand-time))) ;; wait for more data
(let* ((confirmed? #t) ;; random?
(packet (make-packet
current-packet
id
channel
#t
(if confirmed? 'confirmed-data 'unconfirmed-data))))
(when confirmed?
(atomic-box-compare-and-swap! to-confirm #f current-packet))
(put-message upstream-chn (make-event 'start packet))
(sleep time-on-air)
(put-message upstream-chn (make-event 'end packet)))
(set! current-packet (1+ current-packet))
(sleep RECEIVE_DELAY1)
(start-listening!)
(sleep RX1)
(stop-listening!)
(when (atomic-box-ref to-confirm)
(sleep (- RECEIVE_DELAY2 RECEIVE_DELAY1))
(start-listening!)
(sleep RX2)
(stop-listening!))))
(define (downstream)
(forever
(let ((msg (get-message downstream-chn)))
(when (im-listening?)
(match (packet-body msg)
('ack (confirm (packet-id msg))))))))
(lambda ()
(spawn-fiber upstream)
(spawn-fiber downstream)))
(define (make-gateway id upstream downstream)
(define time-on-air 0.01) ;s (TODO)
(define (ack-confirmed-data to channel seq-number)
(spawn-fiber
;; TODO: answer in the second window??
(lambda ()
(sleep RECEIVE_DELAY1)
(let ((packet (make-packet seq-number to channel #f 'ack)))
(put-message downstream (make-event 'start packet))
(sleep time-on-air) ;; TODO: size / data-rate
(put-message downstream (make-event 'end packet))))))
;; Upstream: listen, and answer in new fibers
(lambda ()
(forever
(let ((msg (get-message upstream)))
(ll "Gateway ~a: Data #~a got from ~a"
id
(packet-id msg)
(packet-device-id msg))
(match (packet-body msg)
('confirmed-data
(ack-confirmed-data (packet-device-id msg)
(packet-channel-n msg) ;; TODO: not right
(packet-id msg)))
('unconfirmed-data #f))))))
(define (make-radio in end-devices gateways)
(define started '())
;; TODO: this is broken, only accounts for the interference of the packet
;; that was already being sent, and not from the new one that produced the
;; interference => both should be affected.
(define (interference? msg started-packets)
(any (lambda (x) (= (packet-channel-n msg) (packet-channel-n x)))
started-packets))
(lambda ()
(forever
(let ((ev (get-message in)))
(match ev
(($ <event> 'start msg)
(ll "Device ~a started ~a of packet ~a"
(packet-device-id msg)
(packet-body msg)
(packet-id msg))
(set! started (cons msg started)))
(($ <event> 'end msg)
(ll "Device ~a finished ~a of packet ~a"
(packet-device-id msg)
(packet-body msg)
(packet-id msg))
(set! started
(remove! (lambda (x)
(and (= (packet-id msg) (packet-id x))
(= (packet-device-id msg) (packet-device-id x)))) started))
(if (interference? msg started) ;; TODO: interferences are broken
(ll "Interference!!!!!!")
(if (packet-uplink? msg)
(hash-table-walk gateways
(lambda (k gateway)
(put-message (device-channel gateway) msg)))
(put-message
(device-channel (hash-table-ref end-devices (packet-device-id msg)))
msg)))))))))
(define (run-simulation)
(let* ((radio-chn (make-channel))
(end-devices (make-hash-table))
(gateways (make-hash-table)))
(for-each
(lambda (id)
(let ((chn (make-channel)))
(hash-table-set!
end-devices id
(make-device chn (make-class-a id 1 radio-chn chn)))))
(iota 1))
(for-each
(lambda (id)
(let ((chn (make-channel)))
(hash-table-set!
gateways id
(make-device chn (make-gateway id chn radio-chn)))))
(iota 1 2))
(spawn-fiber (make-radio radio-chn end-devices gateways))
(hash-table-walk end-devices
(lambda (_ device) (spawn-fiber (device-thunk device))))
(hash-table-walk gateways
(lambda (_ device) (spawn-fiber (device-thunk device))))))
(run-fibers
run-simulation
#:drain? #t)
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