1 /*
2  *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef MODULES_CONGESTION_CONTROLLER_PCC_BITRATE_CONTROLLER_H_
12 #define MODULES_CONGESTION_CONTROLLER_PCC_BITRATE_CONTROLLER_H_
13 
14 #include <stdint.h>
15 
16 #include <memory>
17 #include <vector>
18 
19 #include "absl/types/optional.h"
20 #include "api/units/data_rate.h"
21 #include "modules/congestion_controller/pcc/monitor_interval.h"
22 #include "modules/congestion_controller/pcc/utility_function.h"
23 
24 namespace webrtc {
25 namespace pcc {
26 
27 class PccBitrateController {
28  public:
29   PccBitrateController(double initial_conversion_factor,
30                        double initial_dynamic_boundary,
31                        double dynamic_boundary_increment,
32                        double rtt_gradient_coefficient,
33                        double loss_coefficient,
34                        double throughput_coefficient,
35                        double throughput_power,
36                        double rtt_gradient_threshold,
37                        double delay_gradient_negative_bound);
38 
39   PccBitrateController(
40       double initial_conversion_factor,
41       double initial_dynamic_boundary,
42       double dynamic_boundary_increment,
43       std::unique_ptr<PccUtilityFunctionInterface> utility_function);
44 
45   absl::optional<DataRate> ComputeRateUpdateForSlowStartMode(
46       const PccMonitorInterval& monitor_interval);
47 
48   DataRate ComputeRateUpdateForOnlineLearningMode(
49       const std::vector<PccMonitorInterval>& block,
50       DataRate bandwidth_estimate);
51 
52   ~PccBitrateController();
53 
54  private:
55   double ApplyDynamicBoundary(double rate_change, double bitrate);
56   double ComputeStepSize(double utility_gradient);
57 
58   // Dynamic boundary variables:
59   int64_t consecutive_boundary_adjustments_number_;
60   const double initial_dynamic_boundary_;
61   const double dynamic_boundary_increment_;
62 
63   const std::unique_ptr<PccUtilityFunctionInterface> utility_function_;
64   // Step Size variables:
65   int64_t step_size_adjustments_number_;
66   const double initial_conversion_factor_;
67 
68   absl::optional<double> previous_utility_;
69 };
70 
71 }  // namespace pcc
72 }  // namespace webrtc
73 
74 #endif  // MODULES_CONGESTION_CONTROLLER_PCC_BITRATE_CONTROLLER_H_
75