# Cross-Cycled Uplink Resource Allocation over NB-IoT

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## Abstract

**:**

## 1. Introduction

- We believe this is the first paper to consider the cross-cycled resource allocation for the uplink in NB-IoT networks.
- We propose a cross-cycled uplink resource allocation algorithm that can use the subframes of the next NP without causing interference.
- We conducted experiments via simulations using realistic settings. Compared with the two resource allocation algorithms [11,12], the results verify our observation and demonstrate the efficiency of the proposed algorithm, which can reduce more subframes with a smaller NPDCCH period. Moreover, the proposed algorithm can be applied for more different NPDCCH periods.

## 2. System Model and Problem Formulation

#### 2.1. System Model

#### 2.2. Problem Formulation

## 3. Cross-NP Uplink Resource Allocation

#### 3.1. Algorithm Description

Algorithm 1: Cross-NP Uplink Resource Allocation |

Algorithm 2: Transmission-Performance |

Algorithm 3: Subframe-Allocation |

Algorithm 4: NSF-Adjustment |

#### 3.2. Property of the Proposed Algorithm

**Theorem**

**1.**

**Proof.**

## 4. Performance Evaluation

#### 4.1. Simulation Setups

#### 4.2. Simulation Results

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## Abbreviations

NB-IoT | Narrowband Internet of Things |

NPUSCH | Narrowband physical uplink shared channel |

UE | User equipment |

NPDCCH | Narrowband physical downlink control channel |

NPDSCH | Narrowband physical downlink shared channel |

DCI | Downlink control indicator |

3GPP | 3rd generation partnership project |

NP | NPDCCH period |

DL | Downlink frequency |

UL | Uplink frequency |

CE | Coverage enhancement |

NPRACH | Narrowband physical random access channel |

OFDMA | Orthogonal frequency division multiple access |

SNR | Signal-to-noise ratio |

TBS | Transport block size |

## References

- 3GPP TS 36.213 V16.0.0 Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures. Available online: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=2427 (accessed on 18 November 2021).
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**2021**, 8, 962–975. [Google Scholar] [CrossRef] - 3GPP TS 36.331 V16.0.0 Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification. Available online: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=2440 (accessed on 18 November 2021).

**Figure 3.**Concept of cross-cycled resource allocation. (

**a**) some subframes cannot be used by the current NP; (

**b**) a cell can allocate the NPUSCH subframes of the next NP, which cannot be used in the next NP, for a UE without causing wireless interference.

**Figure 4.**Effect of the UE numbers on the number of consumed subframes under different ${R}_{max}$ and G values. (

**a**) ${R}_{max}=8$ and $G=2$. (

**b**) ${R}_{max}=16$ and $G=1.5$. (

**c**) ${R}_{max}=16$ and $G=2$.

**Figure 5.**Effect of the UE numbers on the number of consumed subframes under ${R}_{max}=8$ and $G=1.5$.

**Figure 7.**Effect of UE numbers on the resource utilization under different ${R}_{max}$ and G values. (

**a**) ${R}_{max}=8$ and $G=2$. (

**b**) ${R}_{max}=16$ and $G=1.5$. (

**c**) ${R}_{max}=16$ and $G=2$.

**Figure 8.**Effect of the NPRACH periods on the number of consumed subframes under different ${R}_{max}$ and G values with 2000 UEs. (

**a**) ${R}_{max}=8$ and $G=2$. (

**b**) ${R}_{max}=16$ and $G=1.5$. (

**c**) ${R}_{max}=16$ and $G=2$.

Symbol | Depiction |
---|---|

D | The number of UEs |

P | The consumed NPDCCH periods |

F | The subcarriers in a subframe |

M | The number of modulation and coding indexes |

${\psi}_{d}$ | UE d’s data requirement |

${\widehat{N}}_{d}^{u,m}$ | The data repetition requirement of UE d as unit type u and modulation m is adopted |

${N}_{Rep}$ | The set of repetition numbers for delivering data |

${N}_{Rep}^{\mathcal{D}}$ | The set of repetition numbers for delivering a DCI |

${I}_{RU}$ | The set of resource unit numbers |

U | The number of different unit types |

$\eta ({I}^{h},m)$ | The TBS as ${I}^{h}$ resource units with modulation m is transmitted. |

${f}_{u}$ | The subcarriers occupied by unit type u |

${r}_{p}^{s}$ | The subcarriers used by NPRACHs in subframe s of the p-th NP |

${t}_{u}$ | The subframes needed by unit type u |

L | The length of an NP |

${R}_{max}$ | The number of NPDCCH subframes |

G | The system parameter for determining the length of NPDSCH in an NPDCCH period |

R | The repetitions using for delivering one DCI |

${n}_{p}^{c}$ | The last subframe in a series of NPDCCH subframes for delivering DCI c in the p-th NP |

${\mathcal{DCI}}_{p,d}^{c}$ | The function records whether DCI c of the p-th NP is assigned for UE d or not |

${\widehat{\mathcal{D}}}_{d}$ | The DCI repetition requirement of UE d |

K | The set of scheduling delays |

${t}_{i}^{c}$ | The NPUSCH start subframe as DCI c with delay ${k}_{0}^{i}$ |

${\mathcal{S}}_{p}^{s}$ | The subcarriers assigned for UEs in subframe s of the p-th NP. |

${X}_{p,d}^{u,m}$ | The function records whether the cell decides UE d using unit type u and modulation m in the p-th NP or not |

m | ${\mathit{I}}^{\mathit{h}}$ | |||||||
---|---|---|---|---|---|---|---|---|

1 | 2 | 3 | 4 | 5 | 6 | 8 | 10 | |

1 | 16 | 32 | 56 | 88 | 120 | 152 | 208 | 256 |

2 | 24 | 56 | 88 | 144 | 176 | 208 | 256 | 344 |

3 | 32 | 72 | 144 | 176 | 208 | 256 | 328 | 424 |

4 | 40 | 104 | 176 | 208 | 256 | 328 | 440 | 568 |

5 | 56 | 120 | 208 | 256 | 328 | 408 | 552 | 680 |

6 | 72 | 144 | 224 | 328 | 424 | 504 | 680 | 872 |

7 | 88 | 176 | 256 | 392 | 504 | 600 | 808 | 1032 |

8 | 104 | 224 | 328 | 472 | 584 | 680 | 968 | 1224 |

9 | 120 | 256 | 392 | 536 | 680 | 808 | 1096 | 1352 |

10 | 136 | 296 | 456 | 616 | 776 | 936 | 1256 | 1544 |

11 | 144 | 328 | 504 | 680 | 872 | 1032 | 1384 | 1736 |

12 | 176 | 376 | 584 | 776 | 1000 | 1192 | 1608 | 2024 |

13 | 208 | 440 | 680 | 1000 | 1128 | 1352 | 1800 | 2280 |

14 | 224 | 488 | 744 | 1032 | 1256 | 1544 | 2024 | 2536 |

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**MDPI and ACS Style**

Yu, Y.-J.; Huang, Y.-H.; Shih, Y.-Y.
Cross-Cycled Uplink Resource Allocation over NB-IoT. *Sensors* **2021**, *21*, 7948.
https://doi.org/10.3390/s21237948

**AMA Style**

Yu Y-J, Huang Y-H, Shih Y-Y.
Cross-Cycled Uplink Resource Allocation over NB-IoT. *Sensors*. 2021; 21(23):7948.
https://doi.org/10.3390/s21237948

**Chicago/Turabian Style**

Yu, Ya-Ju, Yu-Hsiang Huang, and Yuan-Yao Shih.
2021. "Cross-Cycled Uplink Resource Allocation over NB-IoT" *Sensors* 21, no. 23: 7948.
https://doi.org/10.3390/s21237948