APC first test

zephcore/include/mesh/Mesh.h

@@ -7,6 +7,9 @@
 
 #include <mesh/Dispatcher.h>
 #include <mesh/ContentionTracker.h>
+#ifdef CONFIG_ZEPHCORE_APC
+#include <mesh/PowerController.h>
+#endif
 #include <mesh/RTC.h>
 
 namespace mesh {
@@ -35,6 +38,11 @@ protected:
 	ContentionTracker _contention;
 	ContentionTracker& getContentionTracker() { return _contention; }
 	const ContentionTracker& getContentionTracker() const { return _contention; }
+#ifdef CONFIG_ZEPHCORE_APC
+	PowerController _power_ctrl;
+	PowerController& getPowerController() { return _power_ctrl; }
+	const PowerController& getPowerController() const { return _power_ctrl; }
+#endif
 	void extendPendingRetransmit(uint32_t hash32);
 
 	DispatcherAction onRecvPacket(Packet *pkt) override;

zephcore/include/mesh/PowerController.h

@@ -0,0 +1,109 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Adaptive Power Control (APC) — echo-based TX power reduction
+ *
+ * Measures link margin by tracking echo packets (flood dupes of
+ * packets we sent or retransmitted, heard back from neighbors).
+ * Feeds per-packet margins into a rolling EMA to produce an
+ * adaptive TX power reduction in dBm.
+ *
+ * Rogue filtering: when 2+ distinct neighbors echo the same packet,
+ * clusters their SNRs within 6 dB of the best.  An isolated high
+ * outlier (rogue, badly placed neighbor) is dropped.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+namespace mesh {
+
+class Packet;
+
+class PowerController {
+public:
+	PowerController();
+
+	/* Enable/disable APC. When disabled, getPowerReduction() returns 0. */
+	void setEnabled(bool en) { _enabled = en; }
+	bool isEnabled() const { return _enabled; }
+
+	/* Set current spreading factor (needed for margin calculation). */
+	void setSF(uint8_t sf) { _sf = sf; }
+
+	/* Called when we send or retransmit a flood packet. */
+	void trackTransmit(uint32_t hash32, uint32_t now_ms);
+
+	/* Called for every received flood dupe.  Updates per-source best
+	 * SNR and source diversity.  Returns true if the dupe matched a
+	 * tracked transmit. */
+	bool recordEcho(uint32_t hash32, int8_t snr_x4,
+			uint8_t first_hop_hash, uint32_t now_ms);
+
+	/* Finalize expired entries, update EMA, adjust power, handle
+	 * staleness.  Call from maintenanceLoop (~5 s). */
+	void tick(uint32_t now_ms);
+
+	/* Current TX power reduction in dBm (0 to MAX_REDUCTION_DB).
+	 * Returns 0 when disabled. */
+	int8_t getPowerReduction() const { return _enabled ? _power_reduction_db : 0; }
+
+	/* Current margin estimate in dB (for diagnostics). */
+	float getMarginEstimate() const;
+
+	/* Source count from most recently finalized entry (diagnostics). */
+	uint8_t getLastSourceCount() const { return _last_source_count; }
+
+	bool isWarmedUp() const { return _finalized_count >= WARMUP_COUNT; }
+	bool isStale(uint32_t now_ms) const;
+
+private:
+	static constexpr int RING_SIZE = 16;
+	static constexpr uint32_t ECHO_WINDOW_MS = 10000;  /* 10s: covers SF12 2-hop echo */
+	static constexpr uint32_t STALE_MS = 120000;       /* 2 min */
+	static constexpr int EMA_SHIFT = 2;                 /* alpha = 1/4 */
+	static constexpr int WARMUP_COUNT = 3;
+	static constexpr int MAX_SOURCES = 3;
+	static constexpr int8_t STEP_DOWN_DB = 3;
+	static constexpr int8_t STEP_UP_DB = 6;
+	static constexpr int8_t MAX_REDUCTION_DB = 12;
+	static constexpr int8_t MIN_TX_POWER_DBM = -9;      /* SX1262 hw min */
+	static constexpr int CLUSTER_WIDTH_X4 = 24;          /* 6 dB in x4 */
+	/* TARGET_MARGIN: 16 dB above SF threshold.
+	 * For SF8 (threshold -10 dB): reduce at SNR > +7, increase at SNR < +5 */
+	static constexpr int TARGET_MARGIN_X4 = 64;          /* 16 dB * 4 */
+	static constexpr int HYSTERESIS_X4 = 4;              /* 1 dB * 4 */
+
+	struct Source {
+		uint8_t hash;
+		int8_t snr_x4;
+	};
+
+	struct EchoEntry {
+		uint32_t hash32;
+		uint32_t timestamp_ms;
+		uint8_t source_count;
+		uint8_t sf_at_track;    /* SF when packet was transmitted */
+		Source sources[MAX_SOURCES];
+		bool active;
+	};
+
+	EchoEntry _ring[RING_SIZE];
+	int _next_idx;
+	int32_t _margin_ema_x256;       /* fixed-point EMA (x4 * 256) */
+	int _finalized_count;
+	uint32_t _last_echo_ms;
+	int8_t _power_reduction_db;
+	bool _enabled;
+	uint8_t _sf;
+	uint8_t _last_source_count;
+
+	void finalizeEntry(int idx);
+	int findEntry(uint32_t hash32) const;
+	int8_t computeRobustSNR(const EchoEntry &entry) const;
+
+	/* SNR threshold for a given SF (x4 fixed point). */
+	static int8_t sfThresholdX4(uint8_t sf);
+};
+
+} /* namespace mesh */

zephcore/include/mesh/Radio.h

@@ -29,6 +29,10 @@ public:
 	virtual float getLastRSSI() const { return 0; }
 	virtual float getLastSNR() const { return 0; }
 
+	/* Adaptive Power Control */
+	virtual void setTxPowerReduction(int8_t reduction_db) { (void)reduction_db; }
+	virtual int8_t getTxPowerReduction() const { return 0; }
+
 	/* Packet statistics */
 	virtual uint32_t getPacketsRecv() const { return 0; }
 	virtual uint32_t getPacketsSent() const { return 0; }