We study algorithms for carrier and rate allocation in cellular systems with distributed components such as a heterogeneous LTE system with macrocells and femtocells. Existing work on LTE systems often involves centra...
详细信息
We study algorithms for carrier and rate allocation in cellular systems with distributed components such as a heterogeneous LTE system with macrocells and femtocells. Existing work on LTE systems often involves centralized techniques or requires significant signaling, and is therefore not always applicable in the presence of femtocells. More distributed CSMA-based algorithms (carrier-sense multiple access) were developed in the context of 802.11 systems and have been proven to be utility optimal. However, the proof typically assumes a single transmission rate on each carrier. Further, it relies on the CSMA collision detection mechanisms to know whether a transmission is feasible. In this paper we present a framework for LTE scheduling that is based on CSMA techniques. In particular we first prove that CSMA-based algorithms can be generalized to handle multiple transmission rates in a multi-carrier setting while maintaining utility optimality. We then show how such an algorithm can be implemented in a heterogeneous LTE system where the existing Channel Quality Indication mechanism is used to decide transmission feasibility.
The development of efficient media access control protocols for new generation networks, such as IEEE 802.16 metropolitan wireless system, is a challenging task nowadays. The problem of designing an efficient random m...
详细信息
ISBN:
(纸本)1424402158
The development of efficient media access control protocols for new generation networks, such as IEEE 802.16 metropolitan wireless system, is a challenging task nowadays. The problem of designing an efficient random multiple accessalgorithm for centralized data network, where subscriber stations transmit bandwidth requests to the base station in an uplink channel, is a focus of the paper. For this purpose special model for a centralized network is considered and new random multiple accessalgorithm is developed and analyzed. This algorithm, further referred to as distributed queue algorithm (Multi-FS-ALOHA), is shown to provide higher tenacity and lower mean delay for the request transmission in comparison to binary exponential backoff, standardized in IEEE 802.16, as well as FS-ALOHA it is based on. Optimization of parameters for the developed algorithm is fulfilled;impact of the noise on its performance is investigated. The analysis is conducted by means of both analytical techniques and simulations.
IEEE 802.16 protocols for metropolitan broadband wireless access systems have been standardized recently. According to the standard, a subscriber station can deliver bandwidth request messages to a base station by num...
详细信息
ISBN:
(纸本)9781424403561
IEEE 802.16 protocols for metropolitan broadband wireless access systems have been standardized recently. According to the standard, a subscriber station can deliver bandwidth request messages to a base station by numerous methods. This paper provides both the simulation and analytical models for the investigation of specified randomaccess method, which is compared with centralized polling and station-grouping mechanisms. Based on the assumptions of Bernoulli request arrival process and ideal channel conditions, the mean delay of a request transmission is evaluated for varying number of transmission opportunities and different arrival rates.
A simple and efficient randomaccess scheme which is suitable for TD-OFDMA systems is proposed in this paper. In the scheme, the network terminals adopt different randomaccess processing methods utilizing the special...
详细信息
ISBN:
(纸本)0780395387
A simple and efficient randomaccess scheme which is suitable for TD-OFDMA systems is proposed in this paper. In the scheme, the network terminals adopt different randomaccess processing methods utilizing the special FRRACH (First Refusal randomaccess CHannel) according to the real-time needs of the traffic. Comparisons of theoretical analysis and simulation results between the proposed scheme and the multiple RACH randomaccess scheme in TD-OFDMA systems show the superiority of the new scheme with respect to both access probability and average delay.
We propose an adaptive random access algorithm for mobile environments with capture. The algorithm has a dynamic window size which is updated according to the traffic intensity. The packet arrival rate is tracked by e...
详细信息
We propose an adaptive random access algorithm for mobile environments with capture. The algorithm has a dynamic window size which is updated according to the traffic intensity. The packet arrival rate is tracked by employing sequential detection procedures. Simulations indicate that reducing the window size adaptively under heavy load conditions improves the average delay significantly. Copyright (C) 2001 John Wiley & Sons, Ltd.
We propose a new packet reservation multiple access (PRMA) scheme for the joint transmission of voice and data traffics in a microcellular medium. The collision resolution protocol within the system is based on a modi...
详细信息
We propose a new packet reservation multiple access (PRMA) scheme for the joint transmission of voice and data traffics in a microcellular medium. The collision resolution protocol within the system is based on a modification of the window random access algorithm, which has superior properties compared to the conventional slotted Aloha. The proposed algorithm, which we call packet reservation window multiple access (PRWMA), works in distinct modes for voice and data without prioritization, and the user performs slightly different operations depending on the information type. Simulation results show that PRWMA outperforms PRMA by a significant margin in terms of voice user capacity.
This paper presents a method of employing a priority scheme in a randomaccess environment. A prioritized nonblocked stack collision resolution algorithm with binary feedback is developed and tested using simulations....
详细信息
This paper presents a method of employing a priority scheme in a randomaccess environment. A prioritized nonblocked stack collision resolution algorithm with binary feedback is developed and tested using simulations. The algorithm accommodates an n-level priority scheme which makes it attractive in mobile data systems. The effectiveness of the algorithm is described on its ability to first, reject the lowest priority class when the system load is near or on the maximum value and second, minimize the delay spread of the higher class users. The performance of the algorithm is characterized using the through-put/delay and cumulative delay for each class of users.
In this paper we introduce the n-ary Multi-slot Stack random access algorithm (msSTART) for use in an IEEE 802.14 hybrid fiber/coaxial (HFC) network. The msSTART random access algorithm (RAA) is an evolution of the st...
详细信息
In this paper we introduce the n-ary Multi-slot Stack random access algorithm (msSTART) for use in an IEEE 802.14 hybrid fiber/coaxial (HFC) network. The msSTART random access algorithm (RAA) is an evolution of the stack-based START algorithm. It is an easy to implement, high-efficiency, free-access, robust, stable RAA optimized to operate in an environment where contention slots could dynamically change. Through a series of simulation studies, we demonstrate the performance advantages of msSTART by comparing its throughput/delay characteristics to those of other popular RAAs, including ALOHA and tree-search RAAs. For the latter RAAs, we also provide a unified stack representation of their operation.
暂无评论