Mbed OS Reference | LoRaPHY.h Source File

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 /**
  *  @file LoRaPHY.h
  *
  *  @brief An abstract class providing radio object to children and
  *         provide base for implementing LoRa PHY layer
  *
  *  \code
  *   ______                              _
  *  / _____)             _              | |
  * ( (____  _____ ____ _| |_ _____  ____| |__
  *  \____ \| ___ |    (_   _) ___ |/ ___)  _ \
  *  _____) ) ____| | | || |_| ____( (___| | | |
  * (______/|_____)_|_|_| \__)_____)\____)_| |_|
  *   (C)2013 Semtech
  *  ___ _____ _   ___ _  _____ ___  ___  ___ ___
  * / __|_   _/_\ / __| |/ / __/ _ \| _ \/ __| __|
  * \__ \ | |/ _ \ (__| ' <| _| (_) |   / (__| _|
  * |___/ |_/_/ \_\___|_|\_\_| \___/|_|_\\___|___|
  * embedded.connectivity.solutions===============
  *
  * \endcode
  *
  * Description: LoRa PHY layer
  *
  * License: Revised BSD License, see LICENSE.TXT file include in the project
  *
  * Maintainer: Miguel Luis ( Semtech ), Gregory Cristian ( Semtech ) and Daniel Jaeckle ( STACKFORCE )
  *
  * Copyright (c) 2017, Arm Limited and affiliates.
  * SPDX-License-Identifier: BSD-3-Clause
  *
  */
 
 #ifndef MBED_OS_LORAPHY_BASE_
 #define MBED_OS_LORAPHY_BASE_
 
 #include "platform/NonCopyable.h"
 
 #include "system/LoRaWANTimer.h"
 #include "LoRaRadio.h"
 #include "lora_phy_ds.h"
 
 /** LoRaPHY Class
  * Parent class for LoRa regional PHY implementations
  */
 class LoRaPHY : private mbed::NonCopyable<LoRaPHY> {
 
 public:
     virtual ~LoRaPHY();
 
     /** Initialize LoRaPHY
      *
      *  LoRaMac calls this to initialize LoRaPHY.
      *
      * @param lora_time a pointer to LoRaWANTimeHandler object
      */
     void initialize(LoRaWANTimeHandler *lora_time);
 
     /** Stores a reference to Radio object.
      *
      * Application is responsible for constructing a 'LoRaRadio' object
      * which is passed down to the PHY layer.
      *
      * @param radio    a reference to radio driver object
      */
     void set_radio_instance(LoRaRadio &radio);
 
     /** Puts radio in sleep mode.
      *
      * Requests the radio driver to enter sleep mode.
      */
     void put_radio_to_sleep(void);
 
     /** Puts radio in standby mode.
      *
      * Requests the radio driver to enter standby mode.
      */
     void put_radio_to_standby(void);
 
     /** Puts radio in receive mode.
      *
      * Requests the radio driver to enter receive mode.
      */
     void handle_receive(void);
 
     /** Delegates MAC layer request to transmit packet.
      *
      * @param buf    a pointer to the data which needs to be transmitted
      *
      * @param size   size of the data in bytes
      */
     void handle_send(uint8_t *buf, uint8_t size);
 
     /** Enables/Disables public network mode.
      *
      * Public and private LoRaWAN network constitute different preambles and
      * Net IDs. This API isused to tell the radio which network mode is in use.
      *
      * @param set    true or false
      */
     void setup_public_network_mode(bool set);
 
     /** Provides a random number from radio.
      *
      * Returns a 32-bit random unsigned integer value based upon RSSI
      * measurements.
      *
      * @return    a 32-bit long random number
      *
      */
     uint32_t get_radio_rng();
 
     /**
      * @brief calculate_backoff Calculates and applies duty cycle back-off time.
      *                          Explicitly updates the band time-off.
      *
      * @param joined                Set to true, if the node has already joined a network, otherwise false.
      * @param last_tx_was_join_req  Set to true, if the last uplink was a join request.
      * @param dc_enabled            Set to true, if the duty cycle is enabled, otherwise false.
      * @param channel               The current channel index.
      * @param elapsed_time          Elapsed time since the start of the node.
      * @param tx_toa                Time-on-air of the last transmission.
      */
     void calculate_backoff(bool joined, bool last_tx_was_join_req, bool dc_enabled, uint8_t channel,
                            lorawan_time_t elapsed_time, lorawan_time_t tx_toa);
 
     /**
       * Tests if a channel is on or off in the channel mask
       */
     bool mask_bit_test(const uint16_t *mask, unsigned bit);
 
     /**
       * Tests if a channel is on or off in the channel mask
       */
     void mask_bit_set(uint16_t *mask, unsigned bit);
 
     /**
       * Tests if a channel is on or off in the channel mask
       */
     void mask_bit_clear(uint16_t *mask, unsigned bit);
 
     /** Entertain a new channel request MAC command.
      *
      * MAC command subsystem processes the new channel request coming form
      * the network server and then MAC layer asks the PHY layer to entertain
      * the request.
      *
      * @param channel_id The channel ID.
      * @param new_channel A pointer to the new channel's parameters.
      *
      * @return bit mask, according to the LoRaWAN spec 1.0.2.
      */
     virtual uint8_t request_new_channel(int8_t channel_id, channel_params_t *new_channel);
 
     /** Process PHY layer state after a successful transmission.
      * @brief set_last_tx_done Updates times of the last transmission for the particular channel and
      *                         band upon which last transmission took place.
      * @param channel The channel in use.
      * @param joined Boolean telling if node has joined the network.
      * @param last_tx_done_time The last TX done time.
      */
     virtual void set_last_tx_done(uint8_t channel, bool joined, lorawan_time_t last_tx_done_time);
 
     /** Enables default channels only.
      *
      * Falls back to a channel mask where only default channels are enabled, all
      * other channels are disabled.
      */
     virtual void restore_default_channels();
 
     /** Processes the incoming CF-list.
      *
      * Handles the payload containing CF-list and enables channels defined
      * therein.
      *
      * @param payload Payload to process.
      * @param size Size of the payload.
      *
      */
     virtual void apply_cf_list(const uint8_t *payload, uint8_t size);
 
     /** Calculates the next datarate to set, when ADR is on or off.
      *
      * @param restore_channel_mask    A boolean set restore channel mask in case
      *                                of failure.
      *
      * @param dr_out                  The calculated datarate for the next TX.
      *
      * @param tx_power_out            The TX power for the next TX.
      *
      * @param adr_ack_counter         The calculated ADR acknowledgement counter.
      *
      * @return True, if an ADR request should be performed.
      */
     bool get_next_ADR(bool restore_channel_mask, int8_t &dr_out,
                       int8_t &tx_power_out, uint32_t &adr_ack_counter);
 
     /** Configure radio reception.
      *
      * @param [in] config    A pointer to the RX configuration.
      *
      * @return True, if the configuration was applied successfully.
      */
     virtual bool rx_config(rx_config_params_t *config);
 
     /** Computing Receive Windows
      *
      * The algorithm tries to calculate the length of receive windows (i.e.,
      * the minimum time it should remain to acquire a lock on the Preamble
      * for synchronization) and the error offset which compensates for the system
      * timing errors. Basic idea behind the algorithm is to optimize for the
      * reception of last 'min_rx_symbols' symbols out of transmitted Premable
      * symbols. The algorithm compensates for the clock drifts, tick granularity
      * and system wake up time (from sleep state) by opening the window early for
      * the lower SFs. For higher SFs, the symbol time is large enough that we can
      * afford to open late (hence the positive offset).
      * The table below shows the calculated values for SF7 to SF12 with 125 kHz
      * bandwidth.
      *
      * +----+-----+----------+---------+-------------------------+----------------------+-------------------------+
      * | SF | BW (kHz) | rx_error (ms) | wake_up (ms) | min_rx_symbols | window_timeout(symb) | window_offset(ms) |
      * +----+-----+----------+---------+-------------------------+----------------------+-------------------------+
      * |  7 |      125 |             5 |            5 |              5 |                   18 |                -7 |
      * |  8 |      125 |             5 |            5 |              5 |                   10 |                -4 |
      * |  9 |      125 |             5 |            5 |              5 |                    6 |                 2 |
      * | 10 |      125 |             5 |            5 |              5 |                    6 |                14 |
      * | 11 |      125 |             5 |            5 |              5 |                    6 |                39 |
      * | 12 |      125 |             5 |            5 |              5 |                    6 |                88 |
      * +----+-----+----------+---------+-------------------------+----------------------+-------------------------+
      *
      * For example for SF7, the receive window will open at downlink start time
      * plus the offset calculated and will remain open for the length window_timeout.
      *
      *             Symbol time = 1.024 ms
      *             Downlink start: T = Tx + 1s (+/- 20 us)
      *                               |
      *                               |
      *                               |
      *                               |
      *                               |
      *                               +---+---+---+---+---+---+---+---+
      *                               |       8 Preamble Symbols      |
      *                               +---+---+---+---+---+---+---+---+
      *   | RX Window start time = T +/- Offset
      *   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
      *   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
      *   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
      *
      * Similarly for SF12:
      *
      *             Symbol time = 32.768 ms
      *             Downlink start: T = Tx + 1s (+/- 20 us)
      *                |
      *                |
      *                |
      *                |
      *                |
      *                +---+---+---+---+---+---+---+---+
      *                |       8 Preamble Symbols      |
      *                +---+---+---+---+---+---+---+---+
      *                           | RX Window start time = T +/- Offset
      *                           +---+---+---+---+---+---+
      *                           |   |   |   |   |   |   |
      *                           +---+---+---+---+---+---+
      */
     /*!
      * Computes the RX window timeout and offset.
      *
      * @param [in] datarate         The RX window datarate index to be used.
      *
      * @param [in] min_rx_symbols   The minimum number of symbols required to
      *                              detect an RX frame.
      *
      * @param [in] rx_error         The maximum timing error of the receiver
      *                              in milliseconds. The receiver will turn on
      *                              in a [-rxError : +rxError] ms interval around
      *                              RxOffset.
      *
      * @param [out] rx_conf_params  Pointer to the structure that needs to be
      *                              filled with receive window parameters.
      *
      */
     virtual void compute_rx_win_params(int8_t datarate, uint8_t min_rx_symbols,
                                        uint32_t rx_error,
                                        rx_config_params_t *rx_conf_params);
 
     /** Configure radio transmission.
      *
      * @param [in]  tx_config    Structure containing tx parameters.
      *
      * @param [out] tx_power     The TX power which will be set.
      *
      * @param [out] tx_toa       The time-on-air of the frame.
      *
      * @return True, if the configuration was applied successfully.
      */
     virtual bool tx_config(tx_config_params_t *tx_config, int8_t *tx_power,
                            lorawan_time_t *tx_toa);
 
     /** Processes a Link ADR Request.
      *
      * @param [in]  params          A pointer ADR request parameters.
      *
      * @param [out] dr_out          The datarate applied.
      *
      * @param [out] tx_power_out    The TX power applied.
      *
      * @param [out] nb_rep_out      The number of repetitions to apply.
      *
      * @param [out] nb_bytes_parsed The number of bytes parsed.
      *
      * @return The status of the operation, according to the LoRaMAC specification.
      */
     virtual uint8_t link_ADR_request(adr_req_params_t *params,
                                      int8_t *dr_out, int8_t *tx_power_out,
                                      uint8_t *nb_rep_out,
                                      uint8_t *nb_bytes_parsed);
 
     /** Accept or rejects RxParamSetupReq MAC command
      *
      * The function processes a RX parameter setup request in response to
      * server MAC command for RX setup.
      *
      * @param [in] params    A pointer to rx parameter setup request.
      *
      * @return The status of the operation, according to the LoRaWAN specification.
      */
     virtual uint8_t accept_rx_param_setup_req(rx_param_setup_req_t *params);
 
     /**
      * @brief accept_tx_param_setup_req Makes decision whether to accept or reject TxParamSetupReq MAC command.
      *
      * @param ul_dwell_time The uplink dwell time.
      * @param dl_dwell_time The downlink dwell time.
      *
      * @return True to let the MAC know that the request is
      *         accepted and MAC can apply TX parameters received
      *         form Network Server. Otherwise false is returned.
      */
     virtual bool accept_tx_param_setup_req(uint8_t ul_dwell_time, uint8_t dl_dwell_time);
 
     /** Processes a DlChannelReq MAC command.
      *
      * @param channel_id The channel ID to add the frequency.
      * @param rx1_frequency The alternative frequency for the Rx1 window.
      *
      * @return The status of the operation, according to the LoRaWAN specification.
      */
     virtual uint8_t dl_channel_request(uint8_t channel_id, uint32_t rx1_frequency);
 
     /** Alternates the datarate of the channel for the join request.
      *
      * @param nb_trials    Number of trials to be made on one given data rate.
      *
      * @return             The datarate to apply .
      */
     virtual int8_t get_alternate_DR(uint8_t nb_trials);
 
     /** Searches and sets the next available channel.
      *
      * If there are multiple channels found available, one of them is selected
      * randomly.
      *
      * @param [in]  nextChanParams Parameters for the next channel.
      *
      * @param [out] channel The next channel to use for TX.
      *
      * @param [out] time The time to wait for the next transmission according to the duty cycle.
      *
      * @param [out] aggregatedTimeOff Updates the aggregated time off.
      *
      * @return Function status [1: OK, 0: Unable to find a channel on the current datarate].
      */
     virtual lorawan_status_t set_next_channel(channel_selection_params_t *nextChanParams,
                                               uint8_t *channel, lorawan_time_t *time,
                                               lorawan_time_t *aggregatedTimeOff);
 
     /** Adds a channel to the channel list.
      *
      * Verifies the channel parameters and if everything is found legitimate,
      * adds that particular channel to the channel list and updates the channel
      * mask.
      *
      * @param [in] new_channel A pointer to the parameters for the new channel.
      * @param [in] id          Channel ID
      *
      * @return LORAWAN_STATUS_OK if everything goes fine, negative error code
      *         otherwise.
      */
     virtual lorawan_status_t add_channel(const channel_params_t *new_channel, uint8_t id);
 
     /** Removes a channel from the channel list.
      *
      * @param [in] channel_id Index of the channel to be removed
      *
      * @return True, if the channel was removed successfully.
      */
     virtual bool remove_channel(uint8_t channel_id);
 
     /** Puts the radio into continuous wave mode.
      *
      * @param [in] continuous_wave   A pointer to the function parameters.
      *
      * @param [in] frequency         Frequency to transmit at
      */
     virtual void set_tx_cont_mode(cw_mode_params_t *continuous_wave,
                                   uint32_t frequency = 0);
 
     /** Computes new data rate according to the given offset
      *
      * @param [in] dr The current datarate.
      *
      * @param [in] dr_offset The offset to be applied.
      *
      * @return     The computed datarate.
      */
     virtual uint8_t apply_DR_offset(int8_t dr, int8_t dr_offset);
 
     /**
      * @brief reset_to_default_values resets some parameters to default values
      * @param params Pointer to MAC protocol parameters which will be reset
      * @param init If true, most of the values will be modified
      */
     void reset_to_default_values(loramac_protocol_params *params, bool init = false);
 
 public:
     /**
      * @brief get_next_lower_tx_datarate Gets the next lower datarate
      * @param datarate Current TX datarate
      * @return Lower datarate than given one or minimum if lower cannot be found anymore
      */
     int8_t get_next_lower_tx_datarate(int8_t datarate);
 
     /**
      * @brief get_minimum_rx_datarate Gets the minimum RX datarate supported by a device
      * @return Minimum RX datarate
      */
     uint8_t get_minimum_rx_datarate();
 
     /**
      * @brief get_minimum_tx_datarate Gets the minimum TX datarate supported by a device
      * @return Minimum TX datarate
      */
     uint8_t get_minimum_tx_datarate();
 
     /**
      * @brief get_default_tx_datarate Gets the default TX datarate
      * @return default TX datarate
      */
     uint8_t get_default_tx_datarate();
 
     /**
      * @brief get_default_max_tx_datarate Gets the maximum achievable data rate for
      *        LoRa modulation. This will always be the highest data rate achievable with
      *        LoRa as defined in the regional specifications.
      * @return Maximum achievable data rate with LoRa modulation.
      */
     uint8_t get_default_max_tx_datarate();
 
     /**
      * @brief get_default_tx_power Gets the default TX power
      * @return Default TX power
      */
     uint8_t get_default_tx_power();
 
     /**
      * @brief get_max_payload Gets maximum amount in bytes which device can send
      * @param datarate A datarate to use
      * @param use_repeater If true repeater table is used, otherwise payloads table is used
      * @return Maximum number of bytes for payload
      */
     uint8_t get_max_payload(uint8_t datarate, bool use_repeater = false);
 
     /**
      * @brief get_maximum_frame_counter_gap Gets maximum frame counter gap
      * @return Maximum frame counter gap
      */
     uint16_t get_maximum_frame_counter_gap();
 
     /**
      * @brief get_ack_timeout Gets timeout value for ACK to be received
      * @return ACK timeout
      */
     uint32_t get_ack_timeout();
 
     /**
      * @brief get_default_rx2_frequency Gets default RX2 frequency
      * @return RX2 frequency
      */
     uint32_t get_default_rx2_frequency();
 
     /**
      * @brief get_default_rx2_datarate Gets default RX2 datarate
      * @return RX2 datarate
      */
     uint8_t get_default_rx2_datarate();
 
     /**
      * @brief get_channel_mask Gets the channel mask
      * @param get_default If true the default mask is returned, otherwise the current mask is returned
      * @return A channel mask
      */
     uint16_t *get_channel_mask(bool get_default = false);
 
     /**
      * @brief get_max_nb_channels Gets maximum number of channels supported
      * @return Number of channels
      */
     uint8_t get_max_nb_channels();
 
     /**
      * @brief get_phy_channels Gets PHY channels
      * @return PHY channels
      */
     channel_params_t *get_phy_channels();
 
     /**
      * @brief is_custom_channel_plan_supported Checks if custom channel plan is supported
      * @return True if custom channel plan is supported, false otherwise
      */
     bool is_custom_channel_plan_supported();
 
     /**
      * @brief get_rx_time_on_air(...) calculates the time the received spent on air
      * @return time spent on air in milliseconds
      */
     uint32_t get_rx_time_on_air(uint8_t modem, uint16_t pkt_len);
 
 public: //Verifiers
 
     /**
      * @brief verify_rx_datarate Verifies that given RX datarate is valid
      * @param datarate Datarate to check
      * @return true if given datarate is valid, false otherwise
      */
     bool verify_rx_datarate(uint8_t datarate);
 
     /**
      * @brief verify_tx_datarate Verifies that given TX datarate is valid
      * @param datarate Datarate to check
      * @param use_default If true validation is done against default value
      * @return true if given datarate is valid, false otherwise
      */
     bool verify_tx_datarate(uint8_t datarate, bool use_default = false);
 
     /**
      * @brief verify_tx_power Verifies that given TX power is valid
      * @param tx_power Power to check
      * @return True if valid, false otherwise
      */
     bool verify_tx_power(uint8_t tx_power);
 
     /**
      * @brief verify_duty_cycle Verifies that given cycle is valid
      * @param cycle Cycle to check
      * @return True if valid, false otherwise
      */
     bool verify_duty_cycle(bool cycle);
 
     /**
      * @brief verify_nb_join_trials Verifies that given number of trials is valid
      * @param nb_join_trials Number to check
      * @return True if valid, false otherwise
      */
     bool verify_nb_join_trials(uint8_t nb_join_trials);
 
 protected:
     LoRaPHY();
 
     /**
      * Looks up corresponding band for a frequency. Returns -1 if not in any band.
      */
     int lookup_band_for_frequency(uint32_t freq) const;
 
     /**
      * Verifies, if a frequency is within a given band.
      */
     virtual bool verify_frequency_for_band(uint32_t freq, uint8_t band) const;
 
     /**
      * Verifies, if a value is in a given range.
      */
     bool val_in_range(int8_t value, int8_t min, int8_t max);
 
     /**
      * Verifies, if a datarate is available on an active channel.
      */
     bool verify_channel_DR(uint16_t *channelsMask, int8_t dr);
 
     /**
      * Disables a channel in a given channels mask.
      */
     bool disable_channel(uint16_t *channel_mask, uint8_t id, uint8_t max_channels);
 
     /**
      * Counts number of bits on in a given mask
      */
     uint8_t count_bits(uint16_t mask, uint8_t nb_bits);
 
     /**
      * Counts the number of active channels in a given channels mask.
      */
     uint8_t num_active_channels(uint16_t *channel_mask, uint8_t start_idx,
                                 uint8_t stop_idx);
 
     /**
      * Copy channel masks.
      */
     void copy_channel_mask(uint16_t *dest_mask, uint16_t *src_mask, uint8_t len);
 
     /**
      * Updates the time-offs of the bands.
      */
     lorawan_time_t update_band_timeoff(bool joined, bool dutyCycle, band_t *bands,
                                        uint8_t nb_bands);
 
     /**
      * Parses the parameter of an LinkAdrRequest.
      */
     uint8_t parse_link_ADR_req(const uint8_t *payload, uint8_t payload_size,
                                link_adr_params_t *adr_params);
 
     /**
      * Verifies and updates the datarate, the TX power and the number of repetitions
      * of a LinkAdrRequest.
      */
     uint8_t verify_link_ADR_req(verify_adr_params_t *verify_params, int8_t *dr,
                                 int8_t *tx_pow, uint8_t *nb_rep);
 
     /**
      * Computes the RX window timeout and the RX window offset.
      */
     void get_rx_window_params(float t_symbol, uint8_t min_rx_symbols,
                               float rx_error, float wakeup_time,
                               uint32_t *window_length, uint32_t *window_length_ms,
                               int32_t *window_offset,
                               uint8_t phy_dr);
 
     /**
      * Computes the txPower, based on the max EIRP and the antenna gain.
      */
     int8_t compute_tx_power(int8_t txPowerIndex, float maxEirp, float antennaGain);
 
     /**
      * Provides a random number in the range provided.
      */
     int32_t get_random(int32_t min, int32_t max);
 
     /**
      * Get next lower data rate
      */
     int8_t get_next_lower_dr(int8_t dr, int8_t min_dr);
 
     /**
      * Get channel bandwidth depending upon data rate table index
      */
     uint8_t get_bandwidth(uint8_t dr_index);
 
     uint8_t enabled_channel_count(uint8_t datarate,
                                   const uint16_t *mask, uint8_t *enabledChannels,
                                   uint8_t *delayTx);
 
     bool is_datarate_supported(const int8_t datarate) const;
 
 private:
 
     /**
      * Computes the symbol time for LoRa modulation.
      */
     float compute_symb_timeout_lora(uint8_t phy_dr, uint32_t bandwidth);
 
     /**
      * Computes the symbol time for FSK modulation.
      */
     float compute_symb_timeout_fsk(uint8_t phy_dr);
 
 protected:
     LoRaRadio *_radio;
     LoRaWANTimeHandler *_lora_time;
     loraphy_params_t phy_params;
 };
 
 #endif /* MBED_OS_LORAPHY_BASE_ */
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