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1.
We consider a joint voice-data packet reservation multiple-access (PRMA) system with transmission errors. Two analysis methods are presented. The first is a combined Markov and equilibrium point analysis. In this method, equilibrium point analysis is used to obtain the equilibrium number of backlogged data terminals, while Markov analysis is used to compute the stationary state probability distribution, assuming the number of backlogged data terminals is equal to the equilibrium value. The second is a Markov analysis using an approximate marginal distribution of backlogged data terminals. System performance measures, namely, voice packet dropping probability, data packet delay, and throughput, are derived in the presence of transmission errors. Computation complexity and accuracy are compared for the two analysis methods. Simulation results are also presented for comparison with analysis results, and good agreement is observed, especially when the packet header error rate is small 相似文献
2.
In this paper, a modified version of the packet reservation multiple-access (PRMA) protocol is proposed to provide spatially dispersed voice and data user terminals wireless access to a base station over a common short-range radio channel. An analytical approach is presented in order to derive system performance in terms of mean data message delay and voice packet dropping probability. A suitable permission probability design is also proposed to enhance system performance. Performance comparisons with an extension of the PRMA protocol to voice data systems previously reported in literature are shown to highlight the better behavior of this approach 相似文献
3.
PRMA, a packetized multiple access scheme for transmitting over short range radio channels, is a promising scheme to implement in a cellular system. PRMA requires little central control and allows hand-overs with minimal base station intervention. However, when mobile voice terminals move from one cell to another, they forfeit the slots reserved for them and, in addition, encounter hand-off delays leading to dropping of voice packets. The main problem is that a mobile terminal can lose more packets even after having secured a reservation. In this paper we use a path enumeration technique using signal flow graphs combined with equilibrium point analysis to analyze the effect of terminal mobility on the performance of PRMA in a cellular environment 相似文献
4.
Performance of PRMA: a packet voice protocol for cellular systems 总被引:19,自引:0,他引:19
Equilibrium point analysis is used to evaluate system behavior in a packet reservation multiple access (PRMA) protocol based network. The authors derive the probability of packet dropping given the number of simultaneous conversations. The authors establish conditions for system stability and efficiency. Numerical calculations based on the theory show close agreement with computer simulations. They also provide valuable guides to system design. Because PRMA is a statistical multiplexer, the channel becomes congested when too many terminals are active. For a particular example it is shown that speech activity detection permits 37 speech terminals to share a PRMA channel with 20 slots per frame, with a packet dropping probability of less than 1% 相似文献
5.
Sheng‐Cheng Yeh Jung‐Shyr Wu Yuan‐Cheng Liang 《International Journal of Communication Systems》2001,14(1):95-104
This paper proposes a new protocol for the integration of voice and video transmission over the packet reservation multiple access (PRMA) system that is a modification of reservation‐ALOHA protocol. We focus on low bit‐rate video applications like video conferencing and visual telephony for wireless communications. The ITU–T H.263 standard provides a solution to the need for low bit‐rate video compression under 64 kbytes/s. The proposed protocol assumes that each voice terminal follows a traffic pattern of talk spurts and silent gaps with fixed permission probability (p=0.3), and each video terminal has the higher permission probability (p=1) to access the available slot based on ITU–T H.263 standard. Again, we present a ‘pseudo‐reservation’ scheme to release slots reserved by video terminals according to the contents of each video transmission buffer, and the active voice terminals can temporarily access the additional slots to improve the performance without sacrificing the video capacity of the system. The packet dropping probability of the active voice terminals and bandwidth utilization of the system are superior to the original PRMA, as indicated in simulation results. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
6.
Fantacci R. Pecorella T. Habib I. 《Selected Areas in Communications, IEEE Journal on》2004,22(3):538-545
This paper deals with a modified version of the packet reservation multiple-access (PRMA) protocol suitable for integration of real-time (voice) and best effort (data) traffic in low Earth orbit (LEO) satellite communication systems. The proposed scheme differs from previous alternatives on the method adopted to handle access requests for voice and data terminals, and to transmit data messages. An analytical approach is proposed and validated in the case of voice and classical (i.e., geometric distributed) data traffic in order to derive system performance in terms of mean data message delay and voice packet dropping probability. However, in order to better highlight the advantages of the proposed approach typical interactive and background traffics types have been also considered. Performance comparisons with previous proposed PRMA protocols for voice and data transmission in LEO satellite communication systems are also shown in order to highlight the better behavior of the proposed scheme. Finally, a brief discussion concerning the extension of the proposed S-PRMA protocol to the case of different satellite communication systems is also provided. 相似文献
7.
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. 相似文献
8.
PRMA (packet reservation multiple access) is a reservation-ALOHA access protocol specifically designed for wireless microcellular
networks that handle both real-time and non-real-time traffic. We present a thorough analysis of this protocol, considering
real-time traffic only, based on a suitable Markov model. The size of the model is such that it can be directly used for an
exact quantitative analysis of the system. In particular, we are able to analyze the packet dropping process, by evaluating
both average and distribution measures. The latter are particularly useful to characterize the degradation caused to real-time
traffic (e.g., voice) by the loss of consecutive packets. Besides, we also derive from the Markov model a qualitative analysis
of the system stability, based on the equilibrium point analysis (EPA) technique. By this technique, we characterize the system
stability and analyze the effect on it of several system parameters (e.g., load, permission probability).
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
In PCS networks, the multiple access problem is characterized by spatially dispersed mobile source terminals sharing a radio
channel connected to a fixed base station. In this paper, we design and evaluate a reservation random access (RRA) scheme
that multiplexes voice traffic at the talkspurt level to efficiently integrate voice and data traffic in outdoor microcellular
environments. The scheme involves partitioning the time frame into two request intervals (voice and data) and an information
interval. Thus, any potential performance degradation caused by voice and data terminals competing for channel access is eliminated.
We consider three random access algorithms for the transmission of voice request packets and one for the transmission of data
request packets. We formulate an approximate Markov model and present analytical results for the steady state voice packet
dropping probability, mean voice access delay and voice throughput. Simulations are used to investigate the steady state voice
packet dropping distribution per talkspurt, and to illustrate preliminary voice-data integration considerations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
A new medium access control (MAC) protocol for mobile wireless communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice and data traffic over two wireless channels, one of medium capacity (referring mostly to outdoor microcellular environments) and one of high capacity (referring to an indoor microcellular environment). Data message arrivals are assumed to occur according to a Poisson process and to vary in length according to a geometric distribution. We evaluate the voice packet dropping probability and access delay, as well as the data packet access and data message transmission delays for various voice and data load conditions. By combining two novel ideas of ours with two useful ideas which have been proposed in other MAC schemes, we are able to remarkably improve the efficiency of a previously proposed MAC scheme [5], and obtain very high voice sources multiplexing results along with most satisfactory voice and data performance and quality of service (QoS) requirements servicing. Our two novel ideas are the sharing of certain request slots among voice and data terminals with priority given to voice, and the use of a fully dynamic low-voice-load mechanism. 相似文献
11.
A new Markovian model is developed to analyze the packet reservation multiple access (PRMA) protocol over Rician fading channels with lognormal shadowing. The packet dropping probability and the voice user capacity are defined as the performance measures. A new formula is derived to evaluate the dropping probability in the fading environment. The analytical results from our new formula show close agreement with those from computer simulations. The capture effect on the PRMA system performance is also studied. We found that, with capture, the user capacity will be improved and the service quality will degrade gracefully when the number of active users in the system increases. Using the dropping probability as the criterion, we also determine the optimal permission probability in a microcellular environment 相似文献
12.
In packet reservation multiple access (PRMA) the receiver in the mobile terminal is required to listen continuously to monitor the acknowledgment messages broadcasted at the end of every time slot. A new scheme for the integration of voice and data based on PRMA is proposed. The voice and the data subsystems are logically separated. The total available bandwidth is divided into three regions-voice information, voice contention, and data regions. The available bandwidth is dynamically partitioned between the above three regions subject to the fulfillment of the quality of service (QoS) requirements of the voice users. The voice subsystem has been modeled as a Markov chain and an exact analytical method used to compute the voice packet dropping probability is described. A nonlinear programming problem is formulated to optimize the bandwidth allocated for the data users. Solutions to this nonlinear programming problem that are very close to optimum have been obtained heuristically. Numerical results indicate that a significant amount of data traffic can be supported without sacrificing the voice capacity of the system 相似文献
13.
14.
Contention-TDMA protocol: performance evaluation 总被引:2,自引:0,他引:2
A hybrid access protocol known, as contention time-division multiple access (C-TDMA), is presented and analyzed in a radio cellular multiuser system scenario. C-TDMA shows some features of contention-based (slotted-ALOHA) and reservation-based (packet reservation multiple access, PRMA) protocols. It has been recommended for use in the uplink of future European multimedia distribution systems. A simple Markov model is proposed to describe C-TDMA behavior. A complete statistical analysis of the model has been made in order to evaluate the performance of the protocol. However, due to the long computation time required in the presence of a large number of users, a simpler approach known as equilibrium point analysis (EPA) is used. Moreover, on the basis of the EPA analysis and the C-TDMA design parameters, a fast algorithm has been developed to improve the achievable throughput of C-TDMA. Results in terms of throughput and delay under variable traffic conditions indicate that C-TDMA is able to grant optimum throughput/delay figures for typical multiuser systems. Moreover, for a digital speech scenario, a performance comparison with PRMA demonstrates that C-TDMA yields equivalent performance to PRMA in terms of number of users supported by the system with a limited packet dropping rate 相似文献
15.
Benelli G. Fantacci R. Giambene G. Ortolani C. 《Vehicular Technology, IEEE Transactions on》2000,49(6):2126-2147
Future mobile communication systems will require new medium access control protocols to attain an efficient multiplexing of different traffic sources while guaranteeing their requirements on quality of service. This paper investigates the performance of a modified packet reservation multiple access (PRMA) protocol, called PRMA with hindering states (PRMA-HS), for supporting voice and data transmissions in mobile cellular systems with high propagation delays. A scenario based on low Earth orbit mobile satellite systems (LEO-MSSs) has been considered, but the analytical approach is general. We have obtained that PRMA-HS achieves a high capacity of voice sources in LEO-MSSs also in the presence of data traffic. A performance analysis has been carried out showing good agreement with simulation results. Finally, the PRMA-HS performance has been evaluated in the presence of different data traffic sources 相似文献
16.
17.
Chung-Ju Chang Bo-Wei Chen Terng-Yuan Liu Fang-Ching Ren 《Selected Areas in Communications, IEEE Journal on》2000,18(2):283-293
The paper proposes congestion control using fuzzy/neural techniques for integrated voice and data direct-sequence code division multiple access/frame reservation multiple access (DS-CDMA/FRMA) cellular networks. The fuzzy/neural congestion controller is constituted by a pipeline recurrent neural network (PRNN) interference predictor, a fuzzy performance indicator, and a fuzzy/neural access probability controller. It regulates the traffic input to the integrated voice and data DS-CDMA/FRMA cellular system by determining proper access probabilities for users so that congestion can be avoided and the throughput can be maximized. Simulation results show that the DS-CDMA/FRMA fuzzy/neural congestion controllers perform better than conventional DS-CDMA/PRMA with channel access function in terms of voice packet dropping ratio, corruption ratio, and utilization. In addition, the neural congestion controller outperforms the fuzzy congestion controller 相似文献
18.
Bianchi G. Borgonovo F. Fratta L. Musumeci L. Zorzi M. 《Vehicular Technology, IEEE Transactions on》1997,46(2):422-436
Packet-switched technology has been demonstrated as effective in cellular radio systems with short propagation delay, not only for data, but also for voice transmission. In fact, packet voice can efficiently exploit speech on-off activity to improve bandwidth utilization over time division multiple access (TDMA). Such an approach has been first suggested in the packet reservation multiple-access (PRMA) technique, an adaptation of the reservation ALOHA protocol to the cellular environment. However, being PRMA-based on a fixed frame scheme, it cannot thoroughly take advantage of the very short propagation delays encountered in microcellular systems that allow, for instance, the immediate retransmission of packets lost because of the interference noise from adjacent cells. We present the centralized PRMA, a natural enhancement of PRMA, in which the base station (BS) plays a central role in scheduling the transmissions of mobile stations (MSs). As a consequence, the transmission scheduling is very flexible and can account for the different traffic rate and delay constraints that emerge from voice and data integration. A packet retransmission policy to recover corrupted packets can be implemented and operated efficiently to provide an acceptable grade of service, even in a very noisy environment. The simulation results presented show the quantitative improvements of the centralized packet reservation multiple-access (C-PRMA) performance with respect to PRMA 相似文献
19.
本文提出了利用用户自身信息之间的相关性区分用户,并适当地调整用户再次竞争信道的允许概率,来提高分组预约多址(PRMA)协议中话音业务性能的方法,从仿真的结果看,该方法降低了话音分组的丢失率。 相似文献
20.
分组预约多址(PRMA)的性能仿真 总被引:9,自引:3,他引:6
本文首先给出了分组预约多址(PRMA)的定义和基本性能,然后通过计算机仿真的方法,分析了话音统计特性对PRMA性能的影响。结果表明PRMA系统容量对话音通信过程中的平均有声期的长度变化不敏感,而对话音通信过程中话音激活因子的变化非常敏感。 相似文献