srsLTE/srsenb/hdr/stack/mac/scheduler_grid.h

/*
 * Copyright 2013-2019 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_SCHEDULER_GRID_H
#define SRSLTE_SCHEDULER_GRID_H

#include "lib/include/srslte/interfaces/sched_interface.h"
#include "scheduler_ue.h"
#include "srslte/common/bounded_bitset.h"
#include "srslte/common/log.h"
#include <vector>

namespace srsenb {

//! Type of Allocation
enum class alloc_type_t { DL_BC, DL_PCCH, DL_RAR, DL_DATA, UL_DATA };

//! Result of alloc attempt
struct alloc_outcome_t {
  enum result_enum { SUCCESS, DCI_COLLISION, RB_COLLISION, ERROR };
  result_enum result = ERROR;
  alloc_outcome_t()  = default;
  alloc_outcome_t(result_enum e) : result(e) {}
              operator result_enum() { return result; }
              operator bool() { return result == SUCCESS; }
              const char* to_string() const;
};

//! Params relative to a single TTI
struct tti_params_t {
  uint32_t tti_rx;
  uint32_t tti_tx_dl;
  uint32_t tti_tx_ul;
  uint32_t sf_idx;
  uint32_t sfn;
  explicit tti_params_t(uint32_t tti_rx_);
};

//! Class responsible for managing a PDCCH CCE grid, namely cce allocs, and avoid collisions.
class pdcch_grid_t
{
public:
  struct alloc_t {
    uint16_t              rnti    = 0;
    srslte_dci_location_t dci_pos = {0, 0};
    pdcch_mask_t          current_mask; ///< this PDCCH alloc mask
    pdcch_mask_t          total_mask;   ///< Accumulation of all PDCCH masks for the current solution (tree route)
  };
  using alloc_result_t = std::vector<const alloc_t*>;

  void init(const sched_params_t& sched_params);
  void new_tti(const tti_params_t& tti_params_, uint32_t start_cfi);
  bool alloc_dci(alloc_type_t alloc_type, uint32_t aggr_idx, sched_ue* user = nullptr);
  bool set_cfi(uint32_t cfi);

  // getters
  uint32_t    get_cfi() const { return current_cfix + 1; }
  void        get_allocs(alloc_result_t* vec = nullptr, pdcch_mask_t* tot_mask = nullptr, size_t idx = 0) const;
  uint32_t    nof_cces() const;
  size_t      nof_allocs() const { return nof_dci_allocs; }
  size_t      nof_alloc_combinations() const { return prev_end - prev_start; }
  std::string result_to_string(bool verbose = false) const;

private:
  const static uint32_t nof_cfis = 3;
  using tree_node_t = std::pair<int, alloc_t>; ///< First represents the parent node idx, and second the alloc tree node

  void                             reset();
  const sched_ue::sched_dci_cce_t* get_cce_loc_table(alloc_type_t alloc_type, sched_ue* user) const;
  void                             update_alloc_tree(int                              node_idx,
                                                     uint32_t                         aggr_idx,
                                                     sched_ue*                        user,
                                                     alloc_type_t                     alloc_type,
                                                     const sched_ue::sched_dci_cce_t* dci_locs);

  // consts
  const sched_params_t* sched_params = nullptr;
  srslte::log*          log_h        = nullptr;

  // tti vars
  const tti_params_t*      tti_params   = nullptr;
  uint32_t                 current_cfix = 0;
  size_t                   prev_start = 0, prev_end = 0;
  std::vector<tree_node_t> dci_alloc_tree;
  size_t                   nof_dci_allocs = 0;
};

//! manages a full TTI grid resources, namely CCE and DL/UL RB allocations
class tti_grid_t
{
public:
  struct dl_ctrl_alloc_t {
    alloc_outcome_t outcome;
    rbg_range_t     rbg_range;
  };

  void            init(const sched_params_t& sched_params_, uint32_t cc_idx_);
  void            new_tti(const tti_params_t& tti_params_, uint32_t start_cfi);
  dl_ctrl_alloc_t alloc_dl_ctrl(uint32_t aggr_lvl, alloc_type_t alloc_type);
  alloc_outcome_t alloc_dl_data(sched_ue* user, const rbgmask_t& user_mask);
  alloc_outcome_t alloc_ul_data(sched_ue* user, ul_harq_proc::ul_alloc_t alloc, bool needs_pdcch);

  // getters
  rbgmask_t&          get_dl_mask() { return dl_mask; }
  const rbgmask_t&    get_dl_mask() const { return dl_mask; }
  prbmask_t&          get_ul_mask() { return ul_mask; }
  const prbmask_t&    get_ul_mask() const { return ul_mask; }
  uint32_t            get_cfi() const { return pdcch_alloc.get_cfi(); }
  const pdcch_grid_t& get_pdcch_grid() const { return pdcch_alloc; }

private:
  alloc_outcome_t alloc_dl(uint32_t aggr_lvl, alloc_type_t alloc_type, rbgmask_t alloc_mask, sched_ue* user = nullptr);

  // consts
  const sched_params_t* sched_params = nullptr;
  srslte::log*          log_h        = nullptr;
  uint32_t              nof_rbgs     = 0;
  uint32_t              si_n_rbg = 0, rar_n_rbg = 0;
  uint32_t              cc_idx = 0;

  // tti const
  const tti_params_t* tti_params = nullptr;
  // derived
  pdcch_grid_t pdcch_alloc = {};

  // internal state
  uint32_t  avail_rbg = 0;
  rbgmask_t dl_mask   = {};
  prbmask_t ul_mask   = {};
};

//! generic interface used by DL scheduler algorithm
class dl_tti_sched_t
{
public:
  virtual alloc_outcome_t  alloc_dl_user(sched_ue* user, const rbgmask_t& user_mask, uint32_t pid) = 0;
  virtual const rbgmask_t& get_dl_mask() const                                                     = 0;
  virtual uint32_t         get_tti_tx_dl() const                                                   = 0;
  virtual uint32_t         get_nof_ctrl_symbols() const                                            = 0;
  virtual bool             is_dl_alloc(sched_ue* user) const                                       = 0;
};

//! generic interface used by UL scheduler algorithm
class ul_tti_sched_t
{
public:
  virtual alloc_outcome_t  alloc_ul_user(sched_ue* user, ul_harq_proc::ul_alloc_t alloc) = 0;
  virtual const prbmask_t& get_ul_mask() const                                           = 0;
  virtual uint32_t         get_tti_tx_ul() const                                         = 0;
  virtual bool             is_ul_alloc(sched_ue* user) const                             = 0;
};

} // namespace srsenb

#endif // SRSLTE_SCHEDULER_GRID_H