diff --git a/go.mod b/go.mod
index fe03158c..c5269e02 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/pion/interceptor
 
-go 1.20
+go 1.21
 
 require (
 	github.com/pion/logging v0.2.2
diff --git a/pkg/bwe/acknowledgment.go b/pkg/bwe/acknowledgment.go
new file mode 100644
index 00000000..3fc75d76
--- /dev/null
+++ b/pkg/bwe/acknowledgment.go
@@ -0,0 +1,21 @@
+package bwe
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/pion/rtcp"
+)
+
+type acknowledgment struct {
+	seqNr     int64
+	size      uint16
+	departure time.Time
+	arrived   bool
+	arrival   time.Time
+	ecn       rtcp.ECN
+}
+
+func (a acknowledgment) String() string {
+	return fmt.Sprintf("seq=%v, departure=%v, arrival=%v", a.seqNr, a.departure, a.arrival)
+}
diff --git a/pkg/bwe/arrival_group_accumulator.go b/pkg/bwe/arrival_group_accumulator.go
new file mode 100644
index 00000000..69bd3498
--- /dev/null
+++ b/pkg/bwe/arrival_group_accumulator.go
@@ -0,0 +1,43 @@
+package bwe
+
+import "time"
+
+type arrivalGroup []acknowledgment
+
+type arrivalGroupAccumulator struct {
+	next          arrivalGroup
+	burstInterval time.Duration
+}
+
+func newArrivalGroupAccumulator() *arrivalGroupAccumulator {
+	return &arrivalGroupAccumulator{
+		next:          make([]acknowledgment, 0),
+		burstInterval: 5 * time.Millisecond,
+	}
+}
+
+func (a *arrivalGroupAccumulator) onPacketAcked(ack acknowledgment) arrivalGroup {
+	if len(a.next) == 0 {
+		a.next = append(a.next, ack)
+		return nil
+	}
+
+	if ack.departure.Sub(a.next[0].departure) < a.burstInterval {
+		a.next = append(a.next, ack)
+		return nil
+	}
+
+	interDepartureTime := ack.departure.Sub(a.next[0].departure)
+	interArrivalTime := ack.arrival.Sub(a.next[len(a.next)-1].arrival)
+	interGroupDelay := interArrivalTime - interDepartureTime
+
+	if interArrivalTime < a.burstInterval && interGroupDelay < 0 {
+		a.next = append(a.next, ack)
+		return nil
+	}
+
+	group := make(arrivalGroup, len(a.next))
+	copy(group, a.next)
+	a.next = arrivalGroup{ack}
+	return group
+}
diff --git a/pkg/bwe/arrival_group_accumulator_test.go b/pkg/bwe/arrival_group_accumulator_test.go
new file mode 100644
index 00000000..31cc2bc4
--- /dev/null
+++ b/pkg/bwe/arrival_group_accumulator_test.go
@@ -0,0 +1,204 @@
+package bwe
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestArrivalGroupAccumulator(t *testing.T) {
+	triggerNewGroupElement := acknowledgment{
+		departure: time.Time{}.Add(time.Second),
+		arrival:   time.Time{}.Add(time.Second),
+	}
+	cases := []struct {
+		name string
+		log  []acknowledgment
+		exp  []arrivalGroup
+	}{
+		{
+			name: "emptyCreatesNoGroups",
+			log:  []acknowledgment{},
+			exp:  []arrivalGroup{},
+		},
+		{
+			name: "createsSingleElementGroup",
+			log: []acknowledgment{
+				{
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(time.Millisecond),
+				},
+				triggerNewGroupElement,
+			},
+			exp: []arrivalGroup{{
+				{
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(time.Millisecond),
+				},
+			},
+			},
+		},
+		{
+			name: "createsTwoElementGroup",
+			log: []acknowledgment{
+				{
+					arrival: time.Time{}.Add(15 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(3 * time.Millisecond),
+					arrival:   time.Time{}.Add(20 * time.Millisecond),
+				},
+				triggerNewGroupElement,
+			},
+			exp: []arrivalGroup{{
+				{
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(15 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(3 * time.Millisecond),
+					arrival:   time.Time{}.Add(20 * time.Millisecond),
+				},
+			}},
+		},
+		{
+			name: "createsTwoArrivalGroups",
+			log: []acknowledgment{
+				{
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(15 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(3 * time.Millisecond),
+					arrival:   time.Time{}.Add(20 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(9 * time.Millisecond),
+					arrival:   time.Time{}.Add(30 * time.Millisecond),
+				},
+				triggerNewGroupElement,
+			},
+			exp: []arrivalGroup{
+				{
+					{
+						arrival: time.Time{}.Add(15 * time.Millisecond),
+					},
+					{
+						departure: time.Time{}.Add(3 * time.Millisecond),
+						arrival:   time.Time{}.Add(20 * time.Millisecond),
+					},
+				},
+				{
+					{
+						departure: time.Time{}.Add(9 * time.Millisecond),
+						arrival:   time.Time{}.Add(30 * time.Millisecond),
+					},
+				},
+			},
+		},
+		{
+			name: "ignoresOutOfOrderPackets",
+			log: []acknowledgment{
+				{
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(15 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(6 * time.Millisecond),
+					arrival:   time.Time{}.Add(34 * time.Millisecond),
+				},
+				{
+					departure: time.Time{}.Add(8 * time.Millisecond),
+					arrival:   time.Time{}.Add(30 * time.Millisecond),
+				},
+				triggerNewGroupElement,
+			},
+			exp: []arrivalGroup{
+				{
+					{
+						departure: time.Time{},
+						arrival:   time.Time{}.Add(15 * time.Millisecond),
+					},
+				},
+				{
+					{
+						departure: time.Time{}.Add(6 * time.Millisecond),
+						arrival:   time.Time{}.Add(34 * time.Millisecond),
+					},
+					{
+						departure: time.Time{}.Add(8 * time.Millisecond),
+						arrival:   time.Time{}.Add(30 * time.Millisecond),
+					},
+				},
+			},
+		},
+		{
+			name: "newGroupBecauseOfInterDepartureTime",
+			log: []acknowledgment{
+				{
+					seqNr:     0,
+					departure: time.Time{},
+					arrival:   time.Time{}.Add(4 * time.Millisecond),
+				},
+				{
+					seqNr:     1,
+					departure: time.Time{}.Add(3 * time.Millisecond),
+					arrival:   time.Time{}.Add(4 * time.Millisecond),
+				},
+				{
+					seqNr:     2,
+					departure: time.Time{}.Add(6 * time.Millisecond),
+					arrival:   time.Time{}.Add(10 * time.Millisecond),
+				},
+				{
+					seqNr:     3,
+					departure: time.Time{}.Add(9 * time.Millisecond),
+					arrival:   time.Time{}.Add(10 * time.Millisecond),
+				},
+				triggerNewGroupElement,
+			},
+			exp: []arrivalGroup{
+				{
+					{
+						seqNr:     0,
+						departure: time.Time{},
+						arrival:   time.Time{}.Add(4 * time.Millisecond),
+					},
+					{
+						seqNr:     1,
+						departure: time.Time{}.Add(3 * time.Millisecond),
+						arrival:   time.Time{}.Add(4 * time.Millisecond),
+					},
+				},
+				{
+					{
+						seqNr:     2,
+						departure: time.Time{}.Add(6 * time.Millisecond),
+						arrival:   time.Time{}.Add(10 * time.Millisecond),
+					},
+					{
+						seqNr:     3,
+						departure: time.Time{}.Add(9 * time.Millisecond),
+						arrival:   time.Time{}.Add(10 * time.Millisecond),
+					},
+				},
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			aga := newArrivalGroupAccumulator()
+			received := []arrivalGroup{}
+			for _, ack := range tc.log {
+				next := aga.onPacketAcked(ack)
+				if next != nil {
+					received = append(received, next)
+				}
+			}
+			assert.Equal(t, tc.exp, received)
+		})
+	}
+}
diff --git a/pkg/bwe/delay_rate_controller.go b/pkg/bwe/delay_rate_controller.go
new file mode 100644
index 00000000..507b55bf
--- /dev/null
+++ b/pkg/bwe/delay_rate_controller.go
@@ -0,0 +1,58 @@
+package bwe
+
+import (
+	"log"
+	"time"
+)
+
+type DelayRateController struct {
+	aga    *arrivalGroupAccumulator
+	last   arrivalGroup
+	kf     *kalman
+	od     *overuseDetector
+	rc     *rateController
+	latest usage
+}
+
+func NewDelayRateController(initialRate int) *DelayRateController {
+	return &DelayRateController{
+		aga:  newArrivalGroupAccumulator(),
+		last: []acknowledgment{},
+		kf:   newKalman(),
+		od:   newOveruseDetector(true),
+		rc:   newRateController(initialRate),
+	}
+}
+
+func (c *DelayRateController) OnPacketAcked(ack acknowledgment) {
+	next := c.aga.onPacketAcked(ack)
+	if next == nil {
+		return
+	}
+	if len(next) == 0 {
+		// ignore empty groups, should never occur
+		return
+	}
+	if len(c.last) == 0 {
+		c.last = next
+		return
+	}
+	interArrivalTime := next[len(next)-1].arrival.Sub(c.last[len(c.last)-1].arrival)
+	interDepartureTime := next[0].departure.Sub(c.last[0].departure)
+	interGroupDelay := interArrivalTime - interDepartureTime
+	estimate := c.kf.updateEstimate(interGroupDelay)
+	c.latest = c.od.update(ack.arrival, estimate)
+	c.last = next
+	log.Printf(
+		"interArrivalTime=%v, interDepartureTime=%v, interGroupDelay=%v, estimate=%v, threshold=%v",
+		interArrivalTime.Nanoseconds(),
+		interDepartureTime.Nanoseconds(),
+		interGroupDelay.Nanoseconds(),
+		estimate.Nanoseconds(),
+		c.od.delayThreshold.Nanoseconds(),
+	)
+}
+
+func (c *DelayRateController) Update(ts time.Time, lastDeliveryRate int, rtt time.Duration) int {
+	return c.rc.update(ts, c.latest, lastDeliveryRate, rtt)
+}
diff --git a/pkg/bwe/delivery_rate_estimator.go b/pkg/bwe/delivery_rate_estimator.go
new file mode 100644
index 00000000..9d18e3a7
--- /dev/null
+++ b/pkg/bwe/delivery_rate_estimator.go
@@ -0,0 +1,87 @@
+package bwe
+
+import (
+	"container/heap"
+	"time"
+)
+
+type deliveryRateHeapItem struct {
+	arrival time.Time
+	size    int
+}
+
+type deliveryRateHeap []deliveryRateHeapItem
+
+// Len implements heap.Interface.
+func (d deliveryRateHeap) Len() int {
+	return len(d)
+}
+
+// Less implements heap.Interface.
+func (d deliveryRateHeap) Less(i int, j int) bool {
+	return d[i].arrival.Before(d[j].arrival)
+}
+
+// Pop implements heap.Interface.
+func (d *deliveryRateHeap) Pop() any {
+	old := *d
+	n := len(old)
+	x := old[n-1]
+	*d = old[0 : n-1]
+	return x
+}
+
+// Push implements heap.Interface.
+func (d *deliveryRateHeap) Push(x any) {
+	*d = append(*d, x.(deliveryRateHeapItem))
+}
+
+// Swap implements heap.Interface.
+func (d deliveryRateHeap) Swap(i int, j int) {
+	d[i], d[j] = d[j], d[i]
+}
+
+type deliveryRateEstimator struct {
+	window        time.Duration
+	latestArrival time.Time
+	history       *deliveryRateHeap
+}
+
+func newDeliveryRateEstimator(window time.Duration) *deliveryRateEstimator {
+	return &deliveryRateEstimator{
+		window:        window,
+		latestArrival: time.Time{},
+		history:       &deliveryRateHeap{},
+	}
+}
+
+func (e *deliveryRateEstimator) OnPacketAcked(arrival time.Time, size int) {
+	if arrival.After(e.latestArrival) {
+		e.latestArrival = arrival
+	}
+	heap.Push(e.history, deliveryRateHeapItem{
+		arrival: arrival,
+		size:    size,
+	})
+}
+
+func (e *deliveryRateEstimator) GetRate() int {
+	deadline := e.latestArrival.Add(-e.window)
+	for len(*e.history) > 0 && (*e.history)[0].arrival.Before(deadline) {
+		heap.Pop(e.history)
+	}
+	earliest := e.latestArrival
+	sum := 0
+	for _, i := range *e.history {
+		if i.arrival.Before(earliest) {
+			earliest = i.arrival
+		}
+		sum += i.size
+	}
+	d := e.latestArrival.Sub(earliest)
+	if d == 0 {
+		return 0
+	}
+	rate := 8 * float64(sum) / d.Seconds()
+	return int(rate)
+}
diff --git a/pkg/bwe/delivery_rate_estimator_test.go b/pkg/bwe/delivery_rate_estimator_test.go
new file mode 100644
index 00000000..15ea3665
--- /dev/null
+++ b/pkg/bwe/delivery_rate_estimator_test.go
@@ -0,0 +1,74 @@
+package bwe
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDeliveryRateEstimator(t *testing.T) {
+	type ack struct {
+		arrival time.Time
+		size    int
+	}
+	cases := []struct {
+		window       time.Duration
+		acks         []ack
+		expectedRate int
+	}{
+		{
+			window:       0,
+			acks:         []ack{},
+			expectedRate: 0,
+		},
+		{
+			window:       time.Second,
+			acks:         []ack{},
+			expectedRate: 0,
+		},
+		{
+			window: time.Second,
+			acks: []ack{
+				{time.Time{}, 1200},
+			},
+			expectedRate: 0,
+		},
+		{
+			window: time.Second,
+			acks: []ack{
+				{time.Time{}.Add(time.Millisecond), 1200},
+			},
+			expectedRate: 0,
+		},
+		{
+			window: time.Second,
+			acks: []ack{
+				{time.Time{}.Add(time.Second), 1200},
+				{time.Time{}.Add(1500 * time.Millisecond), 1200},
+				{time.Time{}.Add(2 * time.Second), 1200},
+			},
+			expectedRate: 28800,
+		},
+		{
+			window: time.Second,
+			acks: []ack{
+				{time.Time{}.Add(500 * time.Millisecond), 1200},
+				{time.Time{}.Add(time.Second), 1200},
+				{time.Time{}.Add(1500 * time.Millisecond), 1200},
+				{time.Time{}.Add(2 * time.Second), 1200},
+			},
+			expectedRate: 28800,
+		},
+	}
+	for i, tc := range cases {
+		t.Run(fmt.Sprintf("%v", i), func(t *testing.T) {
+			e := newDeliveryRateEstimator(tc.window)
+			for _, ack := range tc.acks {
+				e.OnPacketAcked(ack.arrival, ack.size)
+			}
+			assert.Equal(t, tc.expectedRate, e.GetRate())
+		})
+	}
+}
diff --git a/pkg/bwe/duplicate_ack_filter.go b/pkg/bwe/duplicate_ack_filter.go
new file mode 100644
index 00000000..e6753c28
--- /dev/null
+++ b/pkg/bwe/duplicate_ack_filter.go
@@ -0,0 +1,27 @@
+package bwe
+
+import "github.com/pion/interceptor/pkg/ccfb"
+
+type duplicateAckFilter struct {
+	highestAckedBySSRC map[uint32]int64
+}
+
+func newDuplicateAckFilter() *duplicateAckFilter {
+	return &duplicateAckFilter{
+		highestAckedBySSRC: make(map[uint32]int64),
+	}
+}
+
+func (f *duplicateAckFilter) filter(reports map[uint32]*ccfb.PacketReportList) {
+	for ssrc, prl := range reports {
+		n := 0
+		for _, report := range prl.Reports {
+			if highest, ok := f.highestAckedBySSRC[ssrc]; !ok || report.SeqNr > highest {
+				f.highestAckedBySSRC[ssrc] = report.SeqNr
+				prl.Reports[n] = report
+				n++
+			}
+		}
+		prl.Reports = prl.Reports[:n]
+	}
+}
diff --git a/pkg/bwe/duplicate_ack_filter_test.go b/pkg/bwe/duplicate_ack_filter_test.go
new file mode 100644
index 00000000..3813e96e
--- /dev/null
+++ b/pkg/bwe/duplicate_ack_filter_test.go
@@ -0,0 +1,113 @@
+package bwe
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/pion/interceptor/pkg/ccfb"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDuplicateAckFilter(t *testing.T) {
+	cases := []struct {
+		in     []map[uint32]*ccfb.PacketReportList
+		expect []map[uint32]*ccfb.PacketReportList
+	}{
+		{
+			in:     []map[uint32]*ccfb.PacketReportList{},
+			expect: []map[uint32]*ccfb.PacketReportList{},
+		},
+		{
+			in: []map[uint32]*ccfb.PacketReportList{
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports:   []ccfb.PacketReport{},
+					},
+				},
+			},
+			expect: []map[uint32]*ccfb.PacketReportList{
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports:   []ccfb.PacketReport{},
+					},
+				},
+			},
+		},
+		{
+			in: []map[uint32]*ccfb.PacketReportList{
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports: []ccfb.PacketReport{
+							{
+								SeqNr: 1,
+							},
+							{
+								SeqNr: 2,
+							},
+						},
+					},
+				},
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports: []ccfb.PacketReport{
+							{
+								SeqNr: 1,
+							},
+							{
+								SeqNr: 2,
+							},
+							{
+								SeqNr: 3,
+							},
+						},
+					},
+				},
+			},
+			expect: []map[uint32]*ccfb.PacketReportList{
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports: []ccfb.PacketReport{
+							{
+								SeqNr: 1,
+							},
+							{
+								SeqNr: 2,
+							},
+						},
+					},
+				},
+				{
+					0: &ccfb.PacketReportList{
+						Arrival:   time.Time{},
+						Departure: time.Time{},
+						Reports: []ccfb.PacketReport{
+							{
+								SeqNr: 3,
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	for i, tc := range cases {
+		t.Run(fmt.Sprintf("%v", i), func(t *testing.T) {
+			daf := newDuplicateAckFilter()
+			for i, m := range tc.in {
+				daf.filter(m)
+				assert.Equal(t, tc.expect[i], m)
+			}
+		})
+	}
+}
diff --git a/pkg/bwe/exponential_moving_average.go b/pkg/bwe/exponential_moving_average.go
new file mode 100644
index 00000000..9971a1e7
--- /dev/null
+++ b/pkg/bwe/exponential_moving_average.go
@@ -0,0 +1,19 @@
+package bwe
+
+type exponentialMovingAverage struct {
+	initialized bool
+	alpha       float64
+	average     float64
+	variance    float64
+}
+
+func (a *exponentialMovingAverage) update(sample float64) {
+	if !a.initialized {
+		a.average = sample
+		a.initialized = true
+	} else {
+		delta := sample - a.average
+		a.average = a.alpha*sample + (1-a.alpha)*a.average
+		a.variance = (1-a.alpha)*a.variance + a.alpha*(1-a.alpha)*(delta*delta)
+	}
+}
diff --git a/pkg/bwe/exponential_moving_average_test.go b/pkg/bwe/exponential_moving_average_test.go
new file mode 100644
index 00000000..89976b51
--- /dev/null
+++ b/pkg/bwe/exponential_moving_average_test.go
@@ -0,0 +1,122 @@
+package bwe
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// python to generate test cases:
+// import numpy as np
+// import pandas as pd
+// data = np.random.randint(1, 10, size=10)
+// df = pd.DataFrame(data)
+// expectedAvg = df.ewm(alpha=0.9, adjust=False).mean()
+// expectedVar = df.ewm(alpha=0.9, adjust=False).var(bias=True)
+
+func TestExponentialMovingAverage(t *testing.T) {
+	cases := []struct {
+		alpha       float64
+		updates     []float64
+		expectedAvg []float64
+		expectedVar []float64
+	}{
+		{
+			alpha:       0.9,
+			updates:     []float64{},
+			expectedAvg: []float64{},
+			expectedVar: []float64{},
+		},
+		{
+			alpha:   0.9,
+			updates: []float64{1, 2, 3, 4},
+			expectedAvg: []float64{
+				1.000,
+				1.900,
+				2.890,
+				3.889,
+			},
+			expectedVar: []float64{
+				0.000000,
+				0.090000,
+				0.117900,
+				0.122679,
+			},
+		},
+		{
+			alpha:   0.9,
+			updates: []float64{8, 8, 5, 1, 3, 1, 8, 2, 8, 9},
+			expectedAvg: []float64{
+				8.000000,
+				8.000000,
+				5.300000,
+				1.430000,
+				2.843000,
+				1.184300,
+				7.318430,
+				2.531843,
+				7.453184,
+				8.845318,
+			},
+			expectedVar: []float64{
+				0.000000,
+				0.000000,
+				0.810000,
+				1.745100,
+				0.396351,
+				0.345334,
+				4.215372,
+				2.967250,
+				2.987792,
+				0.514117,
+			},
+		},
+		{
+			alpha:   0.9,
+			updates: []float64{7, 5, 6, 7, 3, 6, 8, 9, 5, 5},
+			expectedAvg: []float64{
+				7.000000,
+				5.200000,
+				5.920000,
+				6.892000,
+				3.389200,
+				5.738920,
+				7.773892,
+				8.877389,
+				5.387739,
+				5.038774,
+			},
+			expectedVar: []float64{
+				0.000000,
+				0.360000,
+				0.093600,
+				0.114336,
+				1.374723,
+				0.750937,
+				0.535217,
+				0.188822,
+				1.371955,
+				0.150726,
+			},
+		},
+	}
+	for i, tc := range cases {
+		t.Run(fmt.Sprintf("%v", i), func(t *testing.T) {
+			a := exponentialMovingAverage{
+				alpha:    tc.alpha,
+				average:  0,
+				variance: 0,
+			}
+			avgs := []float64{}
+			vars := []float64{}
+			for _, u := range tc.updates {
+				a.update(u)
+				avgs = append(avgs, a.average)
+				vars = append(vars, a.variance)
+			}
+			assert.InDeltaSlice(t, tc.expectedAvg, avgs, 0.001)
+			assert.InDeltaSlice(t, tc.expectedVar, vars, 0.001)
+		})
+	}
+}
diff --git a/pkg/bwe/kalman.go b/pkg/bwe/kalman.go
new file mode 100644
index 00000000..d6e7dd43
--- /dev/null
+++ b/pkg/bwe/kalman.go
@@ -0,0 +1,92 @@
+package bwe
+
+import (
+	"math"
+	"time"
+)
+
+const (
+	chi = 0.001
+)
+
+type kalmanOption func(*kalman)
+
+type kalman struct {
+	gain                   float64
+	estimate               time.Duration
+	processUncertainty     float64 // Q_i
+	estimateError          float64
+	measurementUncertainty float64
+
+	disableMeasurementUncertaintyUpdates bool
+}
+
+func initEstimate(e time.Duration) kalmanOption {
+	return func(k *kalman) {
+		k.estimate = e
+	}
+}
+
+func initProcessUncertainty(p float64) kalmanOption {
+	return func(k *kalman) {
+		k.processUncertainty = p
+	}
+}
+
+func initEstimateError(e float64) kalmanOption {
+	return func(k *kalman) {
+		k.estimateError = e * e // Only need variance from now on
+	}
+}
+
+func initMeasurementUncertainty(u float64) kalmanOption {
+	return func(k *kalman) {
+		k.measurementUncertainty = u
+	}
+}
+
+func setDisableMeasurementUncertaintyUpdates(b bool) kalmanOption {
+	return func(k *kalman) {
+		k.disableMeasurementUncertaintyUpdates = b
+	}
+}
+
+func newKalman(opts ...kalmanOption) *kalman {
+	k := &kalman{
+		gain:                                 0,
+		estimate:                             0,
+		processUncertainty:                   1e-3,
+		estimateError:                        0.1,
+		measurementUncertainty:               0,
+		disableMeasurementUncertaintyUpdates: false,
+	}
+	for _, opt := range opts {
+		opt(k)
+	}
+	return k
+}
+
+func (k *kalman) updateEstimate(measurement time.Duration) time.Duration {
+	z := measurement - k.estimate
+
+	zms := float64(z.Microseconds()) / 1000.0
+
+	if !k.disableMeasurementUncertaintyUpdates {
+		alpha := math.Pow((1 - chi), 30.0/(1000.0*5*float64(time.Millisecond)))
+		root := math.Sqrt(k.measurementUncertainty)
+		root3 := 3 * root
+		if zms > root3 {
+			k.measurementUncertainty = math.Max(alpha*k.measurementUncertainty+(1-alpha)*root3*root3, 1)
+		} else {
+			k.measurementUncertainty = math.Max(alpha*k.measurementUncertainty+(1-alpha)*zms*zms, 1)
+		}
+	}
+
+	estimateUncertainty := k.estimateError + k.processUncertainty
+	k.gain = estimateUncertainty / (estimateUncertainty + k.measurementUncertainty)
+
+	k.estimate += time.Duration(k.gain * zms * float64(time.Millisecond))
+
+	k.estimateError = (1 - k.gain) * estimateUncertainty
+	return k.estimate
+}
diff --git a/pkg/bwe/kalman_test.go b/pkg/bwe/kalman_test.go
new file mode 100644
index 00000000..0d7968d3
--- /dev/null
+++ b/pkg/bwe/kalman_test.go
@@ -0,0 +1,68 @@
+package bwe
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestKalman(t *testing.T) {
+	cases := []struct {
+		name         string
+		opts         []kalmanOption
+		measurements []time.Duration
+		expected     []time.Duration
+	}{
+		{
+			name:         "empty",
+			opts:         []kalmanOption{},
+			measurements: []time.Duration{},
+			expected:     []time.Duration{},
+		},
+		{
+			name: "kalmanfilter.netExample",
+			opts: []kalmanOption{
+				initEstimate(10 * time.Millisecond),
+				initEstimateError(100),
+				initProcessUncertainty(0.15),
+				initMeasurementUncertainty(0.01),
+			},
+			measurements: []time.Duration{
+				time.Duration(50.45 * float64(time.Millisecond)),
+				time.Duration(50.967 * float64(time.Millisecond)),
+				time.Duration(51.6 * float64(time.Millisecond)),
+				time.Duration(52.106 * float64(time.Millisecond)),
+				time.Duration(52.492 * float64(time.Millisecond)),
+				time.Duration(52.819 * float64(time.Millisecond)),
+				time.Duration(53.433 * float64(time.Millisecond)),
+				time.Duration(54.007 * float64(time.Millisecond)),
+				time.Duration(54.523 * float64(time.Millisecond)),
+				time.Duration(54.99 * float64(time.Millisecond)),
+			},
+			expected: []time.Duration{
+				time.Duration(50.449959 * float64(time.Millisecond)),
+				time.Duration(50.936547 * float64(time.Millisecond)),
+				time.Duration(51.560411 * float64(time.Millisecond)),
+				time.Duration(52.07324 * float64(time.Millisecond)),
+				time.Duration(52.466566 * float64(time.Millisecond)),
+				time.Duration(52.797787 * float64(time.Millisecond)),
+				time.Duration(53.395303 * float64(time.Millisecond)),
+				time.Duration(53.970236 * float64(time.Millisecond)),
+				time.Duration(54.489652 * float64(time.Millisecond)),
+				time.Duration(54.960137 * float64(time.Millisecond)),
+			},
+		},
+	}
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			k := newKalman(append(tc.opts, setDisableMeasurementUncertaintyUpdates(true))...)
+			estimates := []time.Duration{}
+			for _, m := range tc.measurements {
+				estimates = append(estimates, k.updateEstimate(m))
+			}
+			assert.Equal(t, tc.expected, estimates, "%v != %v", tc.expected, estimates)
+		})
+	}
+}
diff --git a/pkg/bwe/loss_rate_controller.go b/pkg/bwe/loss_rate_controller.go
new file mode 100644
index 00000000..e0b08cb6
--- /dev/null
+++ b/pkg/bwe/loss_rate_controller.go
@@ -0,0 +1,48 @@
+package bwe
+
+type LossRateController struct {
+	bitrate  int
+	min, max int
+
+	packetsSinceLastUpdate int
+	arrivedSinceLastUpdate int
+	lostSinceLastUpdate    int
+}
+
+func NewLossRateController(initialRate, minRate, maxRate int) *LossRateController {
+	return &LossRateController{
+		bitrate:                initialRate,
+		min:                    minRate,
+		max:                    maxRate,
+		packetsSinceLastUpdate: 0,
+		arrivedSinceLastUpdate: 0,
+		lostSinceLastUpdate:    0,
+	}
+}
+
+func (l *LossRateController) OnPacketAcked() {
+	l.packetsSinceLastUpdate++
+	l.arrivedSinceLastUpdate++
+}
+
+func (l *LossRateController) OnPacketLost() {
+	l.packetsSinceLastUpdate++
+	l.lostSinceLastUpdate++
+}
+
+func (l *LossRateController) Update(lastDeliveryRate int) int {
+	lossRate := float64(l.lostSinceLastUpdate) / float64(l.packetsSinceLastUpdate)
+	canIncrease := float64(lastDeliveryRate) >= 0.95*float64(l.bitrate)
+	if lossRate > 0.1 {
+		l.bitrate = int(float64(l.bitrate) * (1 - 0.5*lossRate))
+	} else if lossRate < 0.02 && canIncrease {
+		l.bitrate = int(float64(l.bitrate) * 1.05)
+	}
+	l.bitrate = max(min(l.bitrate, l.max), l.min)
+
+	l.packetsSinceLastUpdate = 0
+	l.arrivedSinceLastUpdate = 0
+	l.lostSinceLastUpdate = 0
+
+	return l.bitrate
+}
diff --git a/pkg/bwe/loss_rate_controller_test.go b/pkg/bwe/loss_rate_controller_test.go
new file mode 100644
index 00000000..8b6ac8e7
--- /dev/null
+++ b/pkg/bwe/loss_rate_controller_test.go
@@ -0,0 +1,86 @@
+package bwe
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLossRateController(t *testing.T) {
+	cases := []struct {
+		init, min, max int
+		acked          int
+		lost           int
+		deliveredRate  int
+		expectedRate   int
+	}{
+		{}, // all zeros
+		{
+			init:          100_000,
+			min:           100_000,
+			max:           1_000_000,
+			acked:         0,
+			lost:          0,
+			deliveredRate: 0,
+			expectedRate:  100_000,
+		},
+		{
+			init:          100_000,
+			min:           100_000,
+			max:           1_000_000,
+			acked:         99,
+			lost:          1,
+			deliveredRate: 100_000,
+			expectedRate:  105_000,
+		},
+		{
+			init:          100_000,
+			min:           100_000,
+			max:           1_000_000,
+			acked:         99,
+			lost:          1,
+			deliveredRate: 90_000,
+			expectedRate:  100_000,
+		},
+		{
+			init:          100_000,
+			min:           100_000,
+			max:           1_000_000,
+			acked:         95,
+			lost:          5,
+			deliveredRate: 99_000,
+			expectedRate:  100_000,
+		},
+		{
+			init:          100_000,
+			min:           50_000,
+			max:           1_000_000,
+			acked:         89,
+			lost:          11,
+			deliveredRate: 90_000,
+			expectedRate:  94_500,
+		},
+		{
+			init:          100_000,
+			min:           100_000,
+			max:           1_000_000,
+			acked:         89,
+			lost:          11,
+			deliveredRate: 90_000,
+			expectedRate:  100_000,
+		},
+	}
+	for i, tc := range cases {
+		t.Run(fmt.Sprintf("%v", i), func(t *testing.T) {
+			lrc := NewLossRateController(tc.init, tc.min, tc.max)
+			for i := 0; i < tc.acked; i++ {
+				lrc.OnPacketAcked()
+			}
+			for i := 0; i < tc.lost; i++ {
+				lrc.OnPacketLost()
+			}
+			assert.Equal(t, tc.expectedRate, lrc.Update(tc.deliveredRate))
+		})
+	}
+}
diff --git a/pkg/bwe/overuse_detector.go b/pkg/bwe/overuse_detector.go
new file mode 100644
index 00000000..dd096fc8
--- /dev/null
+++ b/pkg/bwe/overuse_detector.go
@@ -0,0 +1,83 @@
+package bwe
+
+import (
+	"time"
+)
+
+const (
+	kU = 0.01
+	kD = 0.00018
+)
+
+type overuseDetector struct {
+	adaptiveThreshold    bool
+	overUseTimeThreshold time.Duration
+	delayThreshold       time.Duration
+	lastEstimate         time.Duration
+	lastUpdate           time.Time
+	firstOverUse         time.Time
+	inOveruse            bool
+}
+
+func newOveruseDetector(adaptive bool) *overuseDetector {
+	return &overuseDetector{
+		adaptiveThreshold:    adaptive,
+		overUseTimeThreshold: 10 * time.Millisecond,
+		delayThreshold:       12500 * time.Microsecond,
+		lastEstimate:         0,
+		lastUpdate:           time.Time{},
+		firstOverUse:         time.Time{},
+		inOveruse:            false,
+	}
+}
+
+func (d *overuseDetector) update(ts time.Time, estimate time.Duration) usage {
+	if d.adaptiveThreshold {
+		defer d.adaptThreshold(ts, estimate)
+	}
+	if estimate >= d.lastEstimate && estimate > d.delayThreshold {
+		if d.inOveruse && ts.Sub(d.firstOverUse) > d.overUseTimeThreshold {
+			return usageOver
+		}
+		if !d.inOveruse {
+			d.firstOverUse = ts
+		}
+		d.inOveruse = true
+		return usageNormal
+	}
+	if estimate < -d.delayThreshold {
+		d.inOveruse = false
+		return usageUnder
+	}
+	d.inOveruse = false
+	return usageNormal
+}
+
+func (d *overuseDetector) adaptThreshold(ts time.Time, estimate time.Duration) {
+	delta := ts.Sub(d.lastUpdate).Seconds()
+	d.lastUpdate = ts
+	absEstimate := estimate
+	if absEstimate < 0 {
+		absEstimate = -absEstimate
+	}
+	x := absEstimate - d.delayThreshold
+	if x > 15*time.Millisecond {
+		return
+	}
+	var k float64
+	if absEstimate < d.delayThreshold {
+		k = kD
+	} else {
+		k = kU
+	}
+	diff := float64((absEstimate - d.delayThreshold).Nanoseconds())
+	inc := k * delta * diff
+	incDuration := time.Duration(inc)
+	d.delayThreshold = d.delayThreshold + incDuration
+	if d.delayThreshold < 6*time.Millisecond {
+		d.delayThreshold = 6 * time.Millisecond
+	}
+	if d.delayThreshold > 600*time.Millisecond {
+		d.delayThreshold = 600 * time.Millisecond
+	}
+}
diff --git a/pkg/bwe/overuse_detector_test.go b/pkg/bwe/overuse_detector_test.go
new file mode 100644
index 00000000..86603b18
--- /dev/null
+++ b/pkg/bwe/overuse_detector_test.go
@@ -0,0 +1,185 @@
+package bwe
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestOveruseDetectorUpdate(t *testing.T) {
+	type estimate struct {
+		ts       time.Time
+		estimate time.Duration
+	}
+	cases := []struct {
+		name     string
+		adaptive bool
+		values   []estimate
+		expected []usage
+	}{
+		{
+			name:     "noEstimateNoUsageStatic",
+			adaptive: false,
+			values:   []estimate{},
+			expected: []usage{},
+		},
+		{
+			name:     "overuseStatic",
+			adaptive: false,
+			values: []estimate{
+				{time.Time{}, time.Millisecond},
+				{time.Time{}.Add(5 * time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(20 * time.Millisecond), 30 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver},
+		},
+		{
+			name:     "normaluseStatic",
+			adaptive: false,
+			values:   []estimate{{estimate: 0}},
+			expected: []usage{usageNormal},
+		},
+		{
+			name:     "underuseStatic",
+			adaptive: false,
+			values:   []estimate{{estimate: -20 * time.Millisecond}},
+			expected: []usage{usageUnder},
+		},
+		{
+			name:     "noOverUseBeforeDelayStatic",
+			adaptive: false,
+			values: []estimate{
+				{time.Time{}.Add(time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(2 * time.Millisecond), 30 * time.Millisecond},
+				{time.Time{}.Add(30 * time.Millisecond), 50 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver},
+		},
+		{
+			name:     "noOverUseIfEstimateDecreasedStatic",
+			adaptive: false,
+			values: []estimate{
+				{time.Time{}.Add(time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(10 * time.Millisecond), 40 * time.Millisecond},
+				{time.Time{}.Add(20 * time.Millisecond), 50 * time.Millisecond},
+				{time.Time{}.Add(30 * time.Millisecond), 3 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver, usageNormal},
+		},
+		{
+			name:     "noEstimateNoUsageAdaptive",
+			adaptive: true,
+			values:   []estimate{},
+			expected: []usage{},
+		},
+		{
+			name:     "overuseAdaptive",
+			adaptive: true,
+			values: []estimate{
+				{time.Time{}, time.Millisecond},
+				{time.Time{}.Add(5 * time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(20 * time.Millisecond), 30 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver},
+		},
+		{
+			name:     "normaluseAdaptive",
+			adaptive: true,
+			values:   []estimate{{estimate: 0}},
+			expected: []usage{usageNormal},
+		},
+		{
+			name:     "underuseAdaptive",
+			adaptive: true,
+			values:   []estimate{{estimate: -20 * time.Millisecond}},
+			expected: []usage{usageUnder},
+		},
+		{
+			name:     "noOverUseBeforeDelayAdaptive",
+			adaptive: true,
+			values: []estimate{
+				{time.Time{}.Add(time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(2 * time.Millisecond), 30 * time.Millisecond},
+				{time.Time{}.Add(30 * time.Millisecond), 50 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver},
+		},
+		{
+			name:     "noOverUseIfEstimateDecreasedAdaptive",
+			adaptive: true,
+			values: []estimate{
+				{time.Time{}.Add(time.Millisecond), 20 * time.Millisecond},
+				{time.Time{}.Add(10 * time.Millisecond), 40 * time.Millisecond},
+				{time.Time{}.Add(20 * time.Millisecond), 50 * time.Millisecond},
+				{time.Time{}.Add(30 * time.Millisecond), 3 * time.Millisecond},
+			},
+			expected: []usage{usageNormal, usageNormal, usageOver, usageNormal},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			od := newOveruseDetector(tc.adaptive)
+			received := []usage{}
+			for _, e := range tc.values {
+				usage := od.update(e.ts, e.estimate)
+				received = append(received, usage)
+			}
+			assert.Equal(t, tc.expected, received)
+		})
+	}
+}
+
+func TestOveruseDetectorAdaptThreshold(t *testing.T) {
+	cases := []struct {
+		name              string
+		od                *overuseDetector
+		ts                time.Time
+		estimate          time.Duration
+		expectedThreshold time.Duration
+	}{
+		{
+			name:              "minThreshold",
+			od:                &overuseDetector{},
+			ts:                time.Time{},
+			estimate:          0,
+			expectedThreshold: 6 * time.Millisecond,
+		},
+		{
+			name: "increase",
+			od: &overuseDetector{
+				delayThreshold: 12500 * time.Microsecond,
+				lastUpdate:     time.Time{},
+			},
+			ts:                time.Time{}.Add(time.Second),
+			estimate:          25 * time.Millisecond,
+			expectedThreshold: 12625 * time.Microsecond,
+		},
+		{
+			name: "maxThreshold",
+			od: &overuseDetector{
+				delayThreshold: 600 * time.Millisecond,
+				lastUpdate:     time.Time{},
+			},
+			ts:                time.Time{}.Add(time.Second),
+			estimate:          610 * time.Millisecond,
+			expectedThreshold: 600 * time.Millisecond,
+		},
+		{
+			name: "decrease",
+			od: &overuseDetector{
+				delayThreshold: 12500 * time.Microsecond,
+				lastUpdate:     time.Time{},
+			},
+			ts:                time.Time{}.Add(time.Second),
+			estimate:          time.Millisecond,
+			expectedThreshold: time.Duration(12497930),
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc.od.adaptThreshold(tc.ts, tc.estimate)
+			assert.Equal(t, tc.expectedThreshold, tc.od.delayThreshold)
+		})
+	}
+}
diff --git a/pkg/bwe/rate_controller.go b/pkg/bwe/rate_controller.go
new file mode 100644
index 00000000..a9a6f6c1
--- /dev/null
+++ b/pkg/bwe/rate_controller.go
@@ -0,0 +1,76 @@
+package bwe
+
+import (
+	"math"
+	"time"
+)
+
+type rateController struct {
+	s    state
+	rate int
+
+	decreaseFactor float64 // (beta)
+	lastUpdate     time.Time
+	lastDecrease   *exponentialMovingAverage
+}
+
+func newRateController(initialRate int) *rateController {
+	return &rateController{
+		s:              stateIncrease,
+		rate:           initialRate,
+		decreaseFactor: 0.85,
+		lastUpdate:     time.Time{},
+		lastDecrease:   &exponentialMovingAverage{},
+	}
+}
+
+func (c *rateController) update(ts time.Time, u usage, deliveredRate int, rtt time.Duration) int {
+	nextState := c.s.transition(u)
+	c.s = nextState
+
+	if c.s == stateIncrease {
+		var target float64
+		if c.canIncreaseMultiplicatively(float64(deliveredRate)) {
+			window := ts.Sub(c.lastUpdate)
+			target = c.multiplicativeIncrease(float64(c.rate), window)
+		} else {
+			bitsPerFrame := float64(c.rate) / 30.0
+			packetsPerFrame := math.Ceil(bitsPerFrame / (1200 * 8))
+			expectedPacketSizeBits := bitsPerFrame / packetsPerFrame
+			target = c.additiveIncrease(float64(c.rate), int(expectedPacketSizeBits), rtt)
+		}
+		c.rate = int(min(target, 1.5*float64(deliveredRate)))
+	}
+
+	if c.s == stateDecrease {
+		c.rate = int(c.decreaseFactor * float64(deliveredRate))
+		c.lastDecrease.update(float64(c.rate))
+	}
+
+	c.lastUpdate = ts
+
+	return c.rate
+}
+
+func (c *rateController) canIncreaseMultiplicatively(deliveredRate float64) bool {
+	if c.lastDecrease.average == 0 {
+		return true
+	}
+	stdDev := math.Sqrt(c.lastDecrease.variance)
+	lower := c.lastDecrease.average - 3*stdDev
+	upper := c.lastDecrease.average + 3*stdDev
+	return deliveredRate < lower || deliveredRate > upper
+}
+
+func (c *rateController) multiplicativeIncrease(rate float64, window time.Duration) float64 {
+	exponent := min(window.Seconds(), 1.0)
+	eta := math.Pow(1.08, exponent)
+	target := eta * rate
+	return target
+}
+
+func (c *rateController) additiveIncrease(rate float64, expectedPacketSizeBits int, window time.Duration) float64 {
+	alpha := 0.5 * min(window.Seconds(), 1.0)
+	target := rate + max(1000, alpha*float64(expectedPacketSizeBits))
+	return target
+}
diff --git a/pkg/bwe/send_side_bwe.go b/pkg/bwe/send_side_bwe.go
new file mode 100644
index 00000000..21580439
--- /dev/null
+++ b/pkg/bwe/send_side_bwe.go
@@ -0,0 +1,76 @@
+package bwe
+
+import (
+	"log"
+	"time"
+
+	"github.com/pion/interceptor/pkg/ccfb"
+)
+
+type SendSideController struct {
+	daf  *duplicateAckFilter
+	dre  *deliveryRateEstimator
+	lbc  *LossRateController
+	drc  *DelayRateController
+	rate int
+}
+
+func NewSendSideController(initialRate, minRate, maxRate int) *SendSideController {
+	return &SendSideController{
+		daf: newDuplicateAckFilter(),
+		dre: newDeliveryRateEstimator(time.Second),
+		lbc: NewLossRateController(initialRate, minRate, maxRate),
+		drc: NewDelayRateController(initialRate),
+	}
+}
+
+func (c *SendSideController) OnFeedbackReport(reports map[uint32]*ccfb.PacketReportList) int {
+	c.daf.filter(reports)
+
+	var latestReportArrival time.Time
+	var latestReportDeparture time.Time
+	var lastAckedArrival time.Time
+	var lastAckedPacketDeparture time.Time
+
+	acksCount := 0
+	for _, prl := range reports {
+		if prl.Arrival.After(latestReportArrival) {
+			latestReportArrival = prl.Arrival
+			latestReportDeparture = prl.Departure
+		}
+		for _, r := range prl.Reports {
+			if r.Arrived && !r.Arrival.IsZero() { // in some cases we might receive acks without timestamps. Ignore them.
+				c.dre.OnPacketAcked(r.Arrival, int(r.Size))
+				c.lbc.OnPacketAcked()
+				c.drc.OnPacketAcked(acknowledgment{
+					seqNr:     r.SeqNr,
+					size:      r.Size,
+					departure: r.Departure,
+					arrived:   r.Arrived,
+					arrival:   r.Arrival,
+					ecn:       r.ECN,
+				})
+				if r.Departure.After(lastAckedPacketDeparture) {
+					lastAckedPacketDeparture = r.Departure
+					lastAckedArrival = r.Arrival
+				}
+				acksCount++
+			} else {
+				c.lbc.OnPacketLost()
+			}
+		}
+	}
+	if acksCount == 0 {
+		return c.rate
+	}
+
+	pendingTime := latestReportDeparture.Sub(lastAckedArrival)
+	rtt := latestReportArrival.Sub(lastAckedPacketDeparture) - pendingTime
+
+	delivered := c.dre.GetRate()
+	lossTarget := c.lbc.Update(delivered)
+	delayTarget := c.drc.Update(latestReportArrival, delivered, rtt)
+	c.rate = min(lossTarget, delayTarget)
+	log.Printf("rtt=%v, delivered=%v, lossTarget=%v, delayTarget=%v, target=%v", rtt.Microseconds(), delivered, lossTarget, delayTarget, c.rate)
+	return c.rate
+}
diff --git a/pkg/bwe/state.go b/pkg/bwe/state.go
new file mode 100644
index 00000000..70f90069
--- /dev/null
+++ b/pkg/bwe/state.go
@@ -0,0 +1,59 @@
+package bwe
+
+import "fmt"
+
+type state int
+
+const (
+	stateIncrease state = iota
+	stateDecrease
+	stateHold
+)
+
+func (s state) transition(u usage) state {
+	switch s {
+	case stateHold:
+		switch u {
+		case usageOver:
+			return stateDecrease
+		case usageNormal:
+			return stateIncrease
+		case usageUnder:
+			return stateHold
+		}
+
+	case stateIncrease:
+		switch u {
+		case usageOver:
+			return stateDecrease
+		case usageNormal:
+			return stateIncrease
+		case usageUnder:
+			return stateHold
+		}
+
+	case stateDecrease:
+		switch u {
+		case usageOver:
+			return stateDecrease
+		case usageNormal:
+			return stateHold
+		case usageUnder:
+			return stateHold
+		}
+	}
+	return stateIncrease
+}
+
+func (s state) String() string {
+	switch s {
+	case stateIncrease:
+		return "increase"
+	case stateDecrease:
+		return "decrease"
+	case stateHold:
+		return "hold"
+	default:
+		return fmt.Sprintf("invalid state: %d", s)
+	}
+}
diff --git a/pkg/bwe/state_test.go b/pkg/bwe/state_test.go
new file mode 100644
index 00000000..ecc8d1a0
--- /dev/null
+++ b/pkg/bwe/state_test.go
@@ -0,0 +1,27 @@
+package bwe
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestState(t *testing.T) {
+	t.Run("hold", func(t *testing.T) {
+		assert.Equal(t, stateDecrease, stateHold.transition(usageOver))
+		assert.Equal(t, stateIncrease, stateHold.transition(usageNormal))
+		assert.Equal(t, stateHold, stateHold.transition(usageUnder))
+	})
+
+	t.Run("increase", func(t *testing.T) {
+		assert.Equal(t, stateDecrease, stateIncrease.transition(usageOver))
+		assert.Equal(t, stateIncrease, stateIncrease.transition(usageNormal))
+		assert.Equal(t, stateHold, stateIncrease.transition(usageUnder))
+	})
+
+	t.Run("decrease", func(t *testing.T) {
+		assert.Equal(t, stateDecrease, stateDecrease.transition(usageOver))
+		assert.Equal(t, stateHold, stateDecrease.transition(usageNormal))
+		assert.Equal(t, stateHold, stateDecrease.transition(usageUnder))
+	})
+}
diff --git a/pkg/bwe/usage.go b/pkg/bwe/usage.go
new file mode 100644
index 00000000..0c520950
--- /dev/null
+++ b/pkg/bwe/usage.go
@@ -0,0 +1,24 @@
+package bwe
+
+import "fmt"
+
+type usage int
+
+const (
+	usageOver usage = iota
+	usageUnder
+	usageNormal
+)
+
+func (u usage) String() string {
+	switch u {
+	case usageOver:
+		return "overuse"
+	case usageUnder:
+		return "underuse"
+	case usageNormal:
+		return "normal"
+	default:
+		return fmt.Sprintf("invalid usage: %d", u)
+	}
+}