Wireless Communications

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8 Which is the most preferred LTE duplex mode? FDD or TDD? Which are the countries opting for LTE TDD? What forces FDD 3G countries to go for LTE TDD?
By Mohamed Niaz · Larsen and Toubro

Ismat Aldmour · Al Baha University

The answer by Zaid, especially no. 3 will be main driving for LTE-TDD. As WiMax is going away and all is heading to LTE, data companies, like Sprini... [more]

The answer by Zaid, especially no. 3 will be main driving for LTE-TDD. As WiMax is going away and all is heading to LTE, data companies, like Sprinit-USA, which were main advocates of WiMax, which is TDD, will go to TD-LTE rather than to FD-LTE to effectively utilize the spectrum previously assigned to their WiMax systems without the need for paired spectrum. Companies which evolved from the 3GPP stream are more slower in heading to TDD mode of LTE. Thanks. @AlDmour.

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5 What is the reason for using packet fragmentation or packet packing?
By Zaid. Ali · Universiti Malaysia Perlis

Rinki Sharma · M S Ramaiah School of Advanced Studies

Packet fragmentation is done to allow packet transfer over networks with certain Maximum Transfer Unit (MTU). If application data is bigger than MTU s... [more]

Packet fragmentation is done to allow packet transfer over networks with certain Maximum Transfer Unit (MTU). If application data is bigger than MTU supported by the network then packet must be fragmented before they are transmitted over the network. If the packet is bigger than MTU size supported by the network and fragmentation is not allowed, then routers must drop the packet. To avoid this, many protocols support Path MTU (PMTU) discovery and fragment the data accordingly to avoid packets from being dropped. Apart from that, some protocols support data fragmentation to improve performance in noisy environment / in presence of narrow band interference.

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13 What is the best simulator for IEEE 802.11e on matlab or NS2?
By Heba Dawoud · Qatar University

Maarten Weyn · University of Antwerp

Maybe the truetime toolbox is an option?

Maybe the truetime toolbox is an option?

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Question:
New Any idea about the use of ARMA (Auto Regressive Moving Average) model to predict QoS in Ad hoc networks?
The AutoRegressive Moving Average (ARMA) model is used to forecast resources to meet the QoS requirements in ad hoc networks.

The AutoRegressive Moving Average (ARMA) model is used to forecast resources to meet the QoS requirements in ad hoc networks.

By Med Tekaya · École Supérieure des Communications de Tunis

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1 How is the Simulation of mobile agents in sensor networks in NS2 carried out?
By Divya Lohani · Indian Institute of Information Technology Allahabad

Mangesh Ghonge · Jagadambha College of Engg & Technology

plz use MannaSim Framework in ns2..u have to integrate mannasim in ns2..then u can run sensor n/w scripts in ns2..

plz use MannaSim Framework in ns2..u have to integrate mannasim in ns2..then u can run sensor n/w scripts in ns2..

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1 Is hybrid access control method applied in femtocell network by the operator? What is recent research going on hybrid access mechanism?
By Afaz Ahmed · University of Malaya

Faisal Tariq · The Open University (UK)

These definitions are just to classify things in academia. In industry, it depends on place/owner. As far as I know, there is no such incentive scheme... [more]

These definitions are just to classify things in academia. In industry, it depends on place/owner. As far as I know, there is no such incentive scheme applied so far. In home femtos, only owner selected users are allowed (same as you use password for connecting to femto). femto/picos places in metro/shopping malls are mostly hybrid (as we defined in literature). It allows authorised users to connect. regarding the research, there are still lot to do in managing interference. For example think of an scenario of large office building where you have few (let's say 4/5) femtocell access points. you can try to implement hybrid control for optimising different objective functions. Now you can implement user association rule for ensuring 1) Rate Fairness 2) Load balancing 3) Sum Rate Maximisation 4) Energy efficiency and 5) a combined objective function that takes all of the above into considerations. Another simple task you can try to start with is: For a given set of resources and FAPs, allocate users to ensure minimum interference. Also when new users comes in the system, you can apply the same rule and compare with max rate system. There are numerous ideas that can be explored.

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8 Can someone recommend any application (freeware) for drawing tree and graph diagrams?
By Majid Ahmad · Shri Govindram Seksaria Institute of Technology and Science

Philip Healy · University College Cork

If you need to generate graphs automatically then GraphViz is very good: http://www.graphviz.org/

If you need to generate graphs automatically then GraphViz is very good: http://www.graphviz.org/

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1 Latest Wireless Communication technologies
By Chetan Harsha · University of Bristol

Ash Abbas · Aligarh Muslim University

People are now talking about 5G technologies (may be available in 2020). Latest research is going on Smart Radio (or Cognitive Radio). Dynamic Ad hoc ... [more]

People are now talking about 5G technologies (may be available in 2020). Latest research is going on Smart Radio (or Cognitive Radio). Dynamic Ad hoc Wireless Networks (DAWN), Wearable Devices with AI capabilities.

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2 RSRQ, RSRP and SINR: Which one is the best for cell selection decision in LTE HetNet?
By Faisal Tariq · The Open University (UK)

Massimo Condoluci · Università degli Studi Mediterranea di Reggio Calabria

This is a really interesting question. Check this paper, where consider both channel conditions and cell load in cell selection procedures Optimized... [more]

This is a really interesting question. Check this paper, where consider both channel conditions and cell load in cell selection procedures Optimized Fairness Cell Selection for 3GPP LTE-A Macro-Pico HetNets http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6092994 and also this paper Cell selection for range expansion with almost blank subframe in heterogeneous networks http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6362865 I hope they can be useful for you.

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12 Five years back there was a lot of activity in the Wireless Standards Development (WiMax, LTE, ZigBee, UWB). Now only LTE? Have we reached saturation?
By Mohamed Niaz · Larsen and Toubro

Lee McKnight · Syracuse University

In Nice, France today (May 14, 2013) at TM Forum Management World, Ed Nanno of Syracuse University iSchool WiGiT Lab (Wireless Grid Innovation Testbed... [more]

In Nice, France today (May 14, 2013) at TM Forum Management World, Ed Nanno of Syracuse University iSchool WiGiT Lab (Wireless Grid Innovation Testbed) is participating in demos of the Single Sign On/Workplace as a Service Catalyst Project of the Enterprise Cloud Leadership Council, along with Ericsson, Deutsche Telekom, Portugal Telecom Innovacao, Framehawk, TOA Technologies, and UBS In a Bring Your Own Device environment, the focus of most on simplistic network speed formulas, which in practice/delivered performance as others have noted, are never met, is misguided. (4G = marketing slogan; not -anywhere- actual delivered end user performance.) Cloud services composed dynamically across data centers is what folks should be thinking about, and what wireless network and edge device - typically security - issues they raise. Ed is also releasing WiGiT v0.2 open specifications, along with a Workplace as a Service Use Case; WiGiT v0.2 may be downloaded now from http://wigit.ischool.syr.edu; WPaaS Use Case shortly. The future service creation and delivery challenges are all about delivery and composition of applications and user experience across heterogeneous devices and networks. WiGiT v0.2 is a step towards that direction; TM Forum's Frameworx standards are evolving to cover a wider array of cloud services as enterprise IT systems are transformed, and inevitably impinging on - management - of services across multiple frequencies, whether managed from the cloud or the edge. Bottom line is that next gen applications and services must exist across networks and devices; and most regulators and wireless companies, even those talking 5G, are focusing in the wrong direction. Imho. Check out the Workplace as a Service White Paper released this spring from TM Forum for more info, and my recent article with Tyson Brooks, attached.

Securing Wireless Grids: Architecture Designs for Secure WiGLET-to-WiGLET Interfaces × Tyson Brooks, Lee Mcknight

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Question:
New Can we use the same (reconfigurable) transceiver for UWB and Zigbee/WiFi in Matlab?
I am working on hybrid platform UWB+Zigbee/WiFi, I was wondering if we can use the same reconfigurable transceiver on MATLAB? I am on the initial stag... [more]

I am working on hybrid platform UWB+Zigbee/WiFi, I was wondering if we can use the same reconfigurable transceiver on MATLAB? I am on the initial stages of the assignment and according to theory any signal with fractional bandwidth over 0.2 is considered as UWB, that means if we can adjust our transceiver in a way that it gives fractional bandwidth >0.2 it will be UWB and <0.2 means Narrow band. Please guide.

By Kamran Khan · New York University USA

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Question:
Open Generating signals for primary & secondary users in the simulation of cognitive radios
Hi everyone! I'm working on the classification of primary, secondary & attacker signals in the cognitive radios. For simulation through MATLAB, I need... [more]

Hi everyone! I'm working on the classification of primary, secondary & attacker signals in the cognitive radios. For simulation through MATLAB, I need to generate some signals for each of the three categories mentioned above. Can anyone help me how I can do this? or do you know some datasets for this purpose? Thank you

By Vahid Veysi Sabegh · Iran University of Science and Technology

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25 Simulated vs Analytical Results
By Osama Rehman · Sultan Qaboos University

Femi Aderohunmu · University of Otago

I will followup with Osama's question. "Simulated vs Analytical Results". What about any one of this compared with "Real-world Results". The reason fo... [more]

I will followup with Osama's question. "Simulated vs Analytical Results". What about any one of this compared with "Real-world Results". The reason for this question is that, sometimes for the real-word cases you do not have strong mathematical deductions, however, one is able combine Simulation studies and then proceed to implement a real-world testbed. Does it mean that that result might not be as strong compared with Analytical results?

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10 Can I split the whole bandwith in case of OFDMA for each cell according to the user number?
By Afaz Ahmed · University of Malaya

Zaid. Ali · Universiti Malaysia Perlis

first of all, what is your objective behind dividing the bandwidth in this manner ? if you go to divide and reserve a fix amount of bandwidth for eac... [more]

first of all, what is your objective behind dividing the bandwidth in this manner ? if you go to divide and reserve a fix amount of bandwidth for each relay station type, you will loss the centralization of priority and QoS at the base station, then you have to achieve them at each relay station. moreover, bandwidth is not equally allocated among users, it should follow a scheduler that specify an amount based on QoS, service type , modulation and code rates and so on. some application needs small size with fixed period other variable period with large amount ( depend on the application).

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1 How can an adaptive algorithm using LMS error filter be applied to a rayleigh fading channel model?
By Swati Govil · Shree Ganpati Institute of Technology

Pascal Scalart · Université de Rennes 1

Hello, There are several manners to use an adaptive algorithm (such as the LMS) in a receiver. However, the most common use of such an adaptive algo... [more]

Hello, There are several manners to use an adaptive algorithm (such as the LMS) in a receiver. However, the most common use of such an adaptive algorithm is the equalizer. Transmission over wireless channels will introduce intersymbol interference (ISI) . To decrease the effects of ISI, a multi-tap equalizer is often inserted into the receiver. The coefficients of this equalizer are ajusted at each sampling time from the update relation (steepest-descent or gradient approach) of an adaptive algorithm (the LMS algorithm being the most popular).

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5 What is the best way and first step to study the channel estimation in LTE system?
By Ahmed Abdelreheem · Aswan University

Zaid. Ali · Universiti Malaysia Perlis

i think that you have to start with frame structure of LTE. number of subcarriers, slot structure would very helpful to understand the channel estimat... [more]

i think that you have to start with frame structure of LTE. number of subcarriers, slot structure would very helpful to understand the channel estimation.

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3 Is there any way of allocation of frequency in hexagonal cellular network to the BST?
By Gopalji Kushwaha · Gautam Buddh Technical University

Faisal Tariq · The Open University (UK)

if you consider multiple BST, then fractional frequency reuse (FFR) would provide significant performance improvement.

if you consider multiple BST, then fractional frequency reuse (FFR) would provide significant performance improvement.

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3 Data allocation within downlink subframe of Mobile WiMAX system.
By Zaid. Ali · Universiti Malaysia Perlis

Massimo Condoluci · Università degli Studi Mediterranea di Reggio Calabria

I agree with you, since I also think that frequency domain is more "powerfull" I think that, in the scenario you are considering with a mobile station... [more]

I agree with you, since I also think that frequency domain is more "powerfull" I think that, in the scenario you are considering with a mobile station, the allocation in the frequency domain is more suitable. Indeed, fast fading can considerably change the quality perceived over the whole spectrum especially when a user is moving and, as a consequence, i think that an adequate frequency scheduling can better exploit the available spectrum resources

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Question:
Open How to download jsvm reference software using cvs client?
I have problem in downloading the JSVM Reference software. I installed smart wincvs, to download from CVS server. I set all the CVS access parameters,... [more]

I have problem in downloading the JSVM Reference software. I installed smart wincvs, to download from CVS server. I set all the CVS access parameters, respository path, user name and password as given in the jsvm software model. I receive "you could not get authenticated by the cvs server" Details: i/o error while connecting to host pserver

By balaji l · Velammal Institute of Technology

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3 How can we prevent misuse of VoIP?
By Arindam Banerjee · Heritage Institute of Technology

Damian Duda · Military Communication Institute

Can you precisely define what you mean as security? Vulnerabilities or inherent properties of packet-based voice or something other? There are plenty ... [more]

Can you precisely define what you mean as security? Vulnerabilities or inherent properties of packet-based voice or something other? There are plenty of mechanisms for secure voice now. The question is if they are all economicaly justified in a particular context. PS. GSM is circuit switched technology and it seems that will be used for many years.

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2 About rouge AP.
By Rakesh Shrestha

Muhammad Noman · COMSATS Institute of Information Technology

First i would like to tell you that when a wireless node like Laptop, Desktop system with WLAN Card or Smart phones with WLAN scans for the available ... [more]

First i would like to tell you that when a wireless node like Laptop, Desktop system with WLAN Card or Smart phones with WLAN scans for the available wireless networks that doesn't limits themselves on the number of specific available WLAN Networks they will scan and shows you all available networks. Secondly it is also possible for different Wireless Access Points to broadcast same SSID and mostly in the Campus netwok WLAN is deployed in this manner. For the detection of Rogue APs there are many free tools available on internet under the heading WIFI ANALYZERS you can download them easily and in case you don't find them i can also send you some.

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1 What are the emerging strategic trends concerning Mobile Network Operators' approach towards Mobile Applications and Mobile Applications Stores?
By Antonio Ghezzi · Politecnico di Milano

Antonio Ghezzi · Politecnico di Milano

What is the relationship with open innovation and co-opetition in the Mobile Industry?

What is the relationship with open innovation and co-opetition in the Mobile Industry?

Following
Question:
Open Which is the best transceptor IC solution for building your custom WSN?
Requirements: ISM freq. 902-928 MHz, serial port, like SPI, for uC communication.

Requirements: ISM freq. 902-928 MHz, serial port, like SPI, for uC communication.

By S.Y.C. Catunda · Universidade Federal do Rio Grande do Norte

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1 what are the types of QoS policies?
By Zaid. Ali · Universiti Malaysia Perlis

Mustafa Mustafa · Al-Nahrain University

One of the fundamentals of WiMAX MAC layer is designed to support QoS. QoS is achieved based on connection-oriented MAC architecture, where all downli... [more]

One of the fundamentals of WiMAX MAC layer is designed to support QoS. QoS is achieved based on connection-oriented MAC architecture, where all downlink and uplink connections are controlled by the serving BS. WiMAX defines Connection and Service flwo concepts. Where Connection is a unidirectional logical connection between BS and SS. Each connection is identified by CID. While a service floe is a unidirectional flow of packets with a particular set of QoS parameters and is identified by a service flow identifier (SFID). The QoS parameters could include traffic priority, maximum sustained traffic rate, maximum burst rate, minimum tolerable rate, maximum delay, tolerated jitter, and so on. The base station is responsible for issuing the SFID and mapping it to unique CIDs. Service flows can also be mapped to DiffServ code points or MPLS flow labels to enable end-to-end IP-based QoS. To support a wide variety of applications, WiMAX defines five scheduling services that should be supported by the base station MAC scheduler for data transport over a connection: 1. UGS scheduling service flow. 2. rtPS scheduling service flow. 3. ertPS scheduling service flow. 4. nrtPS scheduling service flow. 5. Best Effort scheduling service flow. This is a brief details for the QoS that is supported by WiMAX. This brief definition is based on this book "Fundamentals of WiMAX: Understanding Broadband Wireless Networking" By A.G. Jeffrey and other. http://www.amazon.com/Fundamentals-WiMAX-Understanding-Networking-ebook/dp/B000SEGQRY I hope it is useful.

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10 Broadbroad provisioning and directions
By Ismat Aldmour · Al Baha University

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2 Which scheduling scheme is best for unsolicited grant services in WiMAX?
By Vishal Choudhary · International Institute of Information Technology, Bhubaneswar

Khalid Awan · Universiti Teknologi Malaysia

WiMAX standard is nt providing any meschanism for the scheduling but its the responsiblity of the operator how to manage the resource. as the in mobil... [more]

WiMAX standard is nt providing any meschanism for the scheduling but its the responsiblity of the operator how to manage the resource. as the in mobile WiMAX the channel status is not predicitable so we can apply adaptive modulation.

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Question:
Open Does anyone have phantom routing protocol coding implemented in Castalia?
Currently working with omnett based castalia If any one link or have a source code it would be helpful.

Currently working with omnett based castalia If any one link or have a source code it would be helpful.

By Altis Raja · St. Joseph's College of Engineering, Chennai

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1 Cognitive radio
By Venkatareddy Akumalla · VRS&YRN College of Engineering & Technology

Vadivelu Ramasamy · Sri Krishna College of Technology

Basically your question implies that the PU ans SU are in line of sight hence there is an improvement in rate. But in real time CRN this will not alwa... [more]

Basically your question implies that the PU ans SU are in line of sight hence there is an improvement in rate. But in real time CRN this will not always true because all PU and SU are subject to fading.

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1 Any stable implementation of IEEE 802.11n ?
By Hanen Idoudi · Université de la Manouba

Imad Jamil · France Télécom

Unfortunately, OPNET seems the only simulator that has a stable model for 802.11n to my knowledge.

Unfortunately, OPNET seems the only simulator that has a stable model for 802.11n to my knowledge.

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8 Can we separate electrical energy from electromagnetic waves?
By Arivu Che · Anna University of Technology, Coimbatore

Shyam Ponappa · Centre for Internet and Society

Was that the question, or was it: Is electricity a different form of energy from electromagnetic radiation? If it wasn't his question, it is my quest... [more]

Was that the question, or was it: Is electricity a different form of energy from electromagnetic radiation? If it wasn't his question, it is my question

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