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C++

/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#ifndef SRSLTE_CHANNEL_MAPPING_H
#define SRSLTE_CHANNEL_MAPPING_H
#include <cinttypes>
#include <list>
#include <map>
#include <mutex>
namespace srslte {
/**
* This class manages the mapping between logical and physical channels.
* A physical channel in this class is a carrier index in the radio class, which
* has multiple antenna ports all tuned to the same frequency.
*
* Every group of channels tuned associated with a carrier go through the same band-pass filter. This
* class then manages the allocation of frequencies to these group of channels.
*
* The same object is reused for the reception and transmission.
*
* When the UE wants to tune a logical channel to a new frequency it requests this class
* to provide an available channel that supports this frequency. At that point,
* that channel can not be used anymore until a call to release().
*
*/
class channel_mapping
{
public:
/** Configures a band. A band is defined by an upper and lower frequency boundaries.
* If the upper and lower frequencies are not configured (default is zero), it means
* that they support any frequency
*/
class band_cfg
{
public:
void set(float low_freq_, float high_freq_)
{
low_freq = low_freq_;
high_freq = high_freq_;
}
bool contains(float freq)
{
if (low_freq == 0 && high_freq == 0) {
return true;
} else {
return freq >= low_freq && freq <= high_freq;
}
}
float get_low() { return low_freq; }
float get_high() { return high_freq; }
private:
float low_freq = 0;
float high_freq = 0;
};
/** Each channel is defined by the band it supports and the physical carrier index in the radio
*/
typedef struct {
band_cfg band;
uint32_t carrier_idx;
} channel_cfg_t;
/**
* Sets the channel configuration. If no channels are configured no physical channels can be allocated
* @param channels_
*/
void set_channels(const std::list<channel_cfg_t>& channels_) { available_channels = channels_; }
/**
* Finds an unused physical channel that supports the provided frequency and assigns it to logical channel
* logical_ch
* @param logical_ch logical channel index
* @param freq Frequency (in Hz) that we want to receive/transmitt
* @return true if a physical channel supporting this frequency was found or false otherwise
*/
bool allocate_freq(const uint32_t& logical_ch, const float& freq);
/**
* Releases the allocation of a logical channel allowing to be used in the next call to allocate_freq
* @param logical_ch logical channel index
* @return false if logical_ch is not allocated, true otherwise
*/
bool release_freq(const uint32_t& logical_ch);
/**
* Obtains the carrier index configured in set_channels() in the radio to which the logical channel logical_ch has
* been mapped to
* @param logical_ch logical channel index
* @return <0 if logical_ch is not allocated, true otherwise
*
* @see channel_cfg_t
*/
int get_carrier_idx(const uint32_t& logical_ch);
/**
* Checks if the channel has been allocated using allocate_freq()
*
* @param logical_ch logical channel index
* @return true if the channel is allocated, false otherwise
*/
bool is_allocated(const uint32_t& logical_ch);
private:
std::list<channel_cfg_t> available_channels = {};
std::map<uint32_t, channel_cfg_t> allocated_channels = {};
std::mutex mutex = {};
};
} // namespace srslte
#endif // SRSLTE_CHANNEL_MAPPING_H