دانلود رایگان مقاله لاتین مدولاسیون سلسله مراتبی از سایت الزویر
عنوان فارسی مقاله:
زمان بندی حداکثر وزن با مدولاسیون سلسله مراتبی برای تاخیر کمتر
عنوان انگلیسی مقاله:
Maximum-weight scheduling with hierarchical modulation for lower delay
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
At the physical layer, superposition coding is suggested for broadcast channels to attain reliable communication with two receivers simultaneously [2]. In superposition coding, messages are layered on each other. This way, the destination with worse channel conditions can reliably decode its own message at the base layer and after decoding the message in the base layer, the destination with better channel conditions can understand its own in the enhancement layer. Hierarchical modulation (also known as embedded, asymmetrical, non-uniform or multi-resolution modulation) is a practical way of applying superposition coding [3–6]. In practice, hierarchical modulation is used for video transmission in the digital video broadcasting-terrestrial (DVB-T) standard [7], but it is not yet implemented in cellular or ad hoc networks. In hierarchical modulation, channel code, assigned power level, signal constellation type, constellation size and symbol mapping can be chosen independently for each layer to control the probability of error at each layer separately. Allowing non-uniform spacing between signal points on the signal constellation, hierarchical modulation protects base layer bits more than enhancement layer bits. While the user with better channel conditions can reliably demodulate both base and enhancement layer bits, the user with poor channel conditions can only recover the base layer. The achievable rate region of the Gaussian broadcast channel with practical constellations and channel coding schemes are investigated in [8,9]. In [10–12], the authors use hierarchical constellations to transmit to two users simultaneously. The proposed adaptive modulation method is opportunistic in the sense that a second user is superposed on the first, only if the first user can transmit with the already assigned rate in the presence of the interlayer interference caused by the second user. This way, channel access probability is almost doubled without any loss in spectral efficiency. In a wireless communication network, via scheduling the dynamic nature of the communication medium can be exploited for enhanced throughput, higher stability, lower delay or improved fairness among users. For example, proportionally fair scheduling prioritizes fairness [13], whereas maximum-weight scheduling emphasizes maximum throughput while keeping the system stable [14]. In opportunistic scheduling methods, the user with the best channel quality is selected to improve system performance. However, in all single-user scheduling methods channel access probability is low, leading to high waiting times and long queues. To prevent such adverse effects, multi-user transmission techniques and scheduling algorithms can be designed jointly [15,16]. In [15], network stability problem is studied, when ideal superposition coding schemes of [2] are used in conjunction with maximum-weight scheduling [14]. In [16], a greedy scheduler allows for multiple-access and broadcast transmissions in addition to point-to-point links. In [17], the authors perform joint routing and scheduling, using successive interference cancelation, superposition coding and dirty paper coding in wireless mesh networks. In the literature, there are only a few papers that look into joint modulation and scheduling design. In [18], queueing delays and buffer distributions in a network are analyzed for two-best user opportunistic and hybrid two-user scheduling schemes, when the rate-adaptive hierarchical modulation scheme of [11] is used. In our work, we investigate practical hierarchical modulation schemes and maximum-weight scheduling jointly. Instead of single-user scheduling only, the transmitter can choose to transmit to two users simultaneously. In this case, the scheduler considers the queue lengths and transmission rates to both receivers and computes the weight accordingly.
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کلمات کلیدی:
Maximum-weight scheduling with hierarchical modulation - IEEE Xplore ieeexplore.ieee.org/document/6842509/ by AZ Yalcin - 2014 - Cited by 1 - Related articles In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to achieve lower transmission delays. Via hierarchical modulat. [PDF]Maximum-weight scheduling with hierarchical modulation for lower ... iranarze.ir/wp-content/uploads/2016/10/E2065.pdf ority packets cannot be transmitted. It is shown that, using hierarchical modulation in the presence of packet prioritization, average delay of low priority traffic can ... Maximum-Weight Scheduling with Hierarchical Modulation for Lower ... https://www.researchgate.net/.../304025945_Maximum-Weight_Scheduling_with_Hiera... Jan 5, 2017 - In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to achieve lower transmission delays. Optimization of Hierarchical Modulation for Use of Scalable Media ... asp-eurasipjournals.springeropen.com/articles/10.1155/2010/942638 by Y Liu - 2010 - Cited by 10 - Related articles Apr 7, 2010 - An optimization strategy for Hierarchical Modulation and ... Typically, the LP stream is of a higher bit rate, but lower robustness than the HP one. ..... There is relatively slow motion between the transmitter and the receiver. Maximum-weight scheduling with hierarchical modulation for lower ... https://www.infona.pl/.../bwmeta1.element.elsevier-91ee8492-9ba4-312d-bf1c-da8b8fd... by AZ Yalcin - 2016 - Cited by 1 - Related articles In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to achieve lower transmission delays. Via hierarchical modulation ... Implementing Mobile TV: ATSC Mobile DTV, MediaFLO, DVB-H/SH, ... https://books.google.com/books?isbn=1136032495 Amitabh Kumar, S. Merrill Weiss - 2012 - Language Arts & Disciplines Channel changing delay in DVBH is primarily related to the time slicing scheme and ... DVB Hdoes not use hierarchical modulation with the base layer and the ... transmission conditions,onlythe baselayer is delivered, giving a lower quality but ... Ahmet Zahid Yalcin - Google Scholar Citations scholar.google.com/citations?user=GQXaZywAAAAJ&hl=en Diversity Analysis of Hierarchical Modulation in Wireless Relay Networks. AZ Yalcin ... Maximum-weight scheduling with hierarchical modulation for lower delay. Packet-2 ieee802.org/16/tgm/contrib/C80216m-08_617.pdf Jul 7, 2008 - Transmission Based on Hierarchical Modulation. Document .... Channel Quality Feedback Delay ... Reduce delay of HARQ retransmission. Computational Science and Its Applications - ICCSA 2006: ... https://books.google.com/books?isbn=3540340807 Osvaldo Gervasi, Vipin Kumar, C.J. Kenneth Tan - 2006 - Computers ... Parameters Values Modulation Type Hierarchical 16QAM Normalized delay ... λ lower bound by worst λ 0.0 0.2 18 20 22 24 26 conventional OFDM/16QAM, ...
