Opportunities of hybrid random access protocols for M2M communications in LTE/LTE-A networks

2021 ◽  
pp. 1-20
Author(s):  
Huda Althumali ◽  
Mohamed Othman ◽  
Nor Kamariah Noordin ◽  
Zurina Mohd Hanapi
Keyword(s):  
Congestion Control ◽  
Success Rate ◽  
Access Network ◽  
Random Access ◽  
Collision Resolution ◽  
Substantial Part ◽  
M2m Communications ◽  
Access Protocols ◽  
The Mean ◽  
Hybrid Protocols

Machine-to-machine (M2M) communications on Long-term evolution (LTE) networks form a substantial part for the Internet-of-things (IoT). The random access procedure is the first step for M2M devices to access network resources. Many researchers have attempted to improve the efficiency of the random access procedure. This work revisits the performance of the hybrid random access protocols which combine congestion control techniques with collision resolution techniques. In particular, we investigate two hybrid protocols. The first one combines the pre-backoff (PBO) with tree random access (TRA), and the second one combines dynamic access barring (DAB) with TRA. The probability analysis is presented for both protocols. The performance is evaluated based on the access success rate, the mean throughput, the mean delay, the collision rate and the mean retransmissions. The simulation results show that the hybrid protocols achieve the highest success rate and throughput with moderate delay and low collision rates with a lower mean number of retransmissions compared to three benchmarks that apply either a congestion control or a collision resolution. The opportunities of future developments of hybrid protocols are listed at the end of this paper to highlight the issues that could be investigated to improve the performance of hybrid random access protocols.

scholarly journals Random Access Protocols With Collision Resolution in a Noncoherent Setting

2015 ◽  
Vol 4 (4) ◽  
pp. 445-448 ◽  
Author(s):  
Zoran Utkovski ◽  
Tome Eftimov ◽  
Petar Popovski
Keyword(s):  
Random Access ◽  
Collision Resolution ◽  
Access Protocols

scholarly journals A New Hybrid Protocol for Random Access and Data Transmission Based on Two-Phase ACB Mechanisms for M2M Communications

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Yali Wu ◽  
Ningbo Zhang ◽  
Guixia Kang
Keyword(s):  
Data Transmission ◽  
Access Network ◽  
Random Access ◽  
Two Phase ◽  
Data Packets ◽  
M2m Communications ◽  
Radio Access ◽  
Massive Number ◽  
Key Issues

Machine-to-machine (M2M) communication is considered as one of the key enablers for providing of advanced services and applications. Since M2M features a massive number of user equipment (UE) pieces, one of the key issues is the radio access network (RAN) overload problem for massive connections in M2M communications. In order to improve the number of successful accesses (i.e., the M2M UE pieces that successfully transmit data packets) for M2M communications in the current long term evolution (LTE) systems, we propose a new hybrid protocol for random access (RA) and data transmission based on two-phase access class barring (ACB) mechanisms. Furthermore, the joint optimization algorithm of the two-phase ACB factors and the number of resource blocks (RBs) allocated for RA and data transmission is designed to maximize the number of successful accesses. Finally, simulation results demonstrate that our scheme can significantly improve the number of successful accesses and achieve performance improvement in reducing the grant time.

scholarly journals Access Control and Pilot Allocation for Machine-Type Communications in Crowded Massive MIMO Systems

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1272 ◽  
Author(s):  
Ta-Hoang Vo ◽  
Zhi Ding ◽  
Quoc-Viet Pham ◽  
Won-Joo Hwang
Keyword(s):  
Success Rate ◽  
Massive Mimo ◽  
Time Slot ◽  
Mimo Systems ◽  
Random Access ◽  
Collision Resolution ◽  
Smart Meters ◽  
Limited Bandwidth ◽  
Machine Type ◽  
Control Overhead

Massive machine-type communication (mMTC) in 5G New Radio (5G-NR) or the Internet of Things (IoT) is a network of physical devices such as vehicles, smart meters, sensors, and smart appliances, which can communicate and interact in real time without human intervention. In IoT systems, the number of networked devices is expected to be in the tens of billions, while radio resources remain scarce. To connect the massive number of devices with limited bandwidth, it is crucial to develop new access solutions that can improve resource efficiency and reduce control overhead as well as access delay. The key idea is controlling the number of arrival devices that want to access the system, and then allowing only the strongest device (that has the largest channel gain and each device is able to check whether it is the strongest device) be able to transit to BS. In this paper, we consider a random access problem in massive MIMO context for the collision resolution, in which the access class barring (ACB) factor is dynamically adjusted in each time slot to maximize access success rate for the strongest-user collision resolution (SUCRe) protocol. We propose the dynamic ACB scheme to find optimal ACB factor in the next time slot and then apply SUCRe protocol to achieve a good performance. This method is called dynamic access class barring combined strongest-user collision resolution (DACB-SUCR). In addition, we investigate two different ACB schemes that consist of the fixed ACB and the traffic-aware ACB to compare with the proposed dynamic ACB. Analysis and simulation results demonstrate that, compared with SUCRe protocol, the proposed DACB-SUCR method can remarkably reduce pilot collision, and increase access success rate. It is also shown that the dynamic ACB gives better performance than the fixed ACB and the traffic-aware ACB.

Modern Random Access Protocols

2016 ◽  
Author(s):  
Matteo Berioli ◽  
Giuseppe Cocco ◽  
Gianluigi Liva ◽  
Andrea Munari
Keyword(s):  
Random Access ◽  
Access Protocols

CLINICAL CHARACTERISTICS OF THE CHRONIC DACRYOCYSTITIS AND THE SUCCESS RATE OF EXTERNAL DACRYOCYSTORHINOSTOMY

2015 ◽  
pp. 29-34
Author(s):  
Van Nam Phan ◽  
Ba Kien Tran
Keyword(s):  
Success Rate ◽  
Key Words ◽  
Clinical Characteristics ◽  
Lacrimal Duct ◽  
Interventional Study ◽  
Chronic Dacryocystitis ◽  
External Dacryocystorhinostomy ◽  
The Mean

Purpose: To determine the clinical characteristics of the chronic dacryocystitis and the success rate of external dacryocystorhinostomy. Methods: The retrospective, interventional study without comparing on 27 patients (32 eyes) of chronic dacryocystitis who underwent dacryocystorhinostomy (DCR) from 2010 to 2011. Results were evaluated with standards: epiphora, purelence, lacrimal duct irrigation. Results: Over period of 6 months, 27 patients including 25 (92.59%) female, 2 (7.41%) male. The mean age was 49.8 years (range, 22-79 years). All patients demonstrated epiphera (range, 3 months – 11 years). Dacryocystorhinostomy was performed unilaterally in 81.48%, bilateral 18.52%. Successrate was 90.06% overall. Conclusions: Although techniques in dacryocystorhinostomy of DUPUY-DUTEMPS is old, its result is mainstay of treatment for chronic dacryocystitis in Vietnam. Key words: Dupuy-Dutemps, chronic dacryocystitis

RESULTS OF INTRALESIONAL TRIAMCINOLONE ACETONIDE FOR CHALAZION TREATMENT

2011 ◽  
pp. 100-104
Author(s):  
Thi Thu Nguyen ◽  
Viet Hien Vo ◽  
Thi Em Do
Keyword(s):  
Success Rate ◽  
Key Words ◽  
Triamcinolone Acetonide ◽  
Lower Eyelid ◽  
Upper Eyelid ◽  
Interventional Trial ◽  
The Mean ◽  
First Time

The study use intralesional triamcinolone acetonide injection proceduce for chalazion treatment.1. Objectives: To evaluate results of intralesional triamcinolone acetonide injection for chalazion treatment. 2. Method: This noncomparative prospective interventional trial included 72 chalazions of 61 patients. 3. Results: 61 patients (72 chalazions) with 19 males (31.1%) và 42 females (68.9%), the mean age was 24 ± 9,78 years. 31.1% patients was the first time chalazion and 68.9% patients was more than one times chalazion including 78.6% patients was recurrent at the first position and 21.4% patients occur at new position. 72 chalazions with 16 (22.2%) chalazions was treated before and 56 (77.8%) chalazions wasn’t done that. 72 chalazions with 49 chalazions (68.1%) are local in upper eyelid and 23 chalazions (31.9%) are local in lower eyelid. The mean of chalazion diameter is 6.99 ± 3.03mm. Intralesional triamcinolone acetonide is injected to treat 72 chalazions with 16 (22.2%) chalazions are injected through the route of skin and 56 (77.8%) chalazions are injected through the route of conjunctiva. After 2 weeks follow-up, the success rate was 93.1% and 6.9% failed. 4. Conclusion: intralesional triamcinolone acetonide injection for chalazion treatment is really effective. Key words: chalazion, intralesional triamcinolone acetonide.

Surgical correction of severe congenital ptosis using a modified frontalis muscle advancement technique: A single-arm trial

2021 ◽  
pp. 112067212199575
Author(s):  
Lei Zhang ◽  
Mingyu Ren ◽  
Yuqing Yan ◽  
Wenjuan Zhai ◽  
Lihong Yang ◽  
...  
Keyword(s):  
Success Rate ◽  
Advancement Flap ◽  
Orbicularis Muscle ◽  
Congenital Ptosis ◽  
Inferior Margin ◽  
Field Of Vision ◽  
Vertical Incision ◽  
Registration Number ◽  
The Mean

Purpose: To describe our experience with a modified frontal muscle advancement flap to treat patients with severe congenital ptosis. Methods: Analysis of the clinical charts of 154 patients who underwent a modified frontal muscle advancement flap. The FM was exposed by a crease incision. The FM flap was created by deep dissection between the orbicularis muscle and orbital septum from the skin crease incision to the supraorbital margin and subcutaneous dissection from the inferior margin of the eyebrow to 0.5 cm above the eyebrow. No vertical incision was made on the FM flap to ensure an intact flap wide enough to cover the entire upper tarsal plate. Contour, symmetry of height, marginal reflex distance (MRD1), and complications were assessed. Mean follow-up was 10 months. Results: The mean patient age was 7.6 ± 5.6 (range, 2–18) years. The mean MRD1 was 3.2 ± 1.3 mm after the operation. All bilateral cases achieved symmetry and optimal lid contour; 17 unilateral cases were under corrected, with a success rate of 89.0%. Complications such as entropion, exposure keratitis, FM paralysis, frontal hypoesthesia, severe haematoma, and entropion were not observed in our series. Conclusion: A modified frontal muscle advancement flap produced a high success rate with a clear field of vision, mild trauma, and few complications. This technique is relatively simple and should be considered for correcting severe congenital ptosis. Date of registration: 29-03-2020 Trial registration number: ChiCTR2000031364 Registration site: http://www.chictr.org/

scholarly journals Unilateral lateral rectus recession is an effective surgery for intermittent exotropia in young children

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Oriel Spierer ◽  
Abraham Spierer
Keyword(s):  
Young Children ◽  
Success Rate ◽  
Lateral Rectus ◽  
Intermittent Exotropia ◽  
Age At Surgery ◽  
Surgical Methods ◽  
Before And After ◽  
The Mean ◽  
Consecutive Esotropia

Abstract Background Different surgical methods have been suggested for the correction of intermittent exotropia. Unilateral lateral rectus recession has been described as a surgical alternative for small and moderate-angle exotropia. In general, previous studies did not focus on the outcomes of unilateral lateral rectus recession in young children with intermittent exotropia. The purpose of this study is to evaluate the surgical outcomes of unilateral lateral rectus recession in the treatment of moderate-angle exotropia (≤ 25 PD (prism diopters)) in children. Methods The charts of all patients younger than 12 years of age with moderate-angle exotropia (up to 25 PD) who were operated during the years 2006–2018 were retrospectively reviewed. Fifty-eight patients underwent unilateral lateral rectus recession and had a minimum follow up of 6 months. The angle of exotropia (PD) before and after surgery and the success rate were documented. Results Mean age at surgery was 6.4 ± 1.9 (range 3.5–11.0) years. Exotropia improved from a preoperative angle of 21.4 ± 4.0 PD to 3.5 ± 5.9 PD postoperatively (p < 0.001). Success rate, defined as deviation of ≤ 10 PD, was achieved in 86.2%. There were 2 (3.4%) cases of overcorrection (consecutive esotropia). There were no intra- or postoperative complications. The mean follow-up duration after surgery was 2.3 ± 1.7 years. Conclusions In children with moderate angle exotropia, good postoperative success rate was achieved by performing unilateral lateral rectus recession.

scholarly journals Endoscopic Stricturotomy Is an Efficacious Option for Management of Strictures in Patients With Inflammatory Bowel Disease

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Nabeeha Mohy-ud-din ◽  
Gursimran S Kochhar
Keyword(s):  
Inflammatory Bowel Disease ◽  
Success Rate ◽  
Bowel Disease ◽  
Chart Review ◽  
Common Complication ◽  
Technical Success ◽  
Technical Success Rate ◽  
Safe Technique ◽  
Inflammatory Bowel ◽  
The Mean

Abstract Background Strictures are a common complication for patients with inflammatory bowel disease. Endoscopic stricturotomy (ESt) is a novel procedure for treatment of these strictures. Methods A chart review was performed for patients with strictures who underwent ESt. Results Eleven patients were included in the study and the total number of strictures treated was 12. The mean length of the strictures was 10.25 ± 4.36 mm. Technical success was achieved in 92% (n = 11) of the procedures. Postprocedural bleeding occurred in 9% (n = 1) of patients, and none of the patients had complications of infection or perforation. Conclusions ESt is a safe technique with high technical success rate.

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