Free Essay


In: Computers and Technology

Submitted By flclri
Words 2509
Pages 11
| | |
|Getting Started | |

One’s understanding of network protocols can often be greatly deepened by “seeing protocols in action” and by “playing around with protocols” – observing the sequence of messages exchanged between two protocol entities, delving down into the details of protocol operation, and causing protocols to perform certain actions and then observing these actions and their consequences. This can be done in simulated scenarios or in a “real” network environment such as the Internet. In the Wireshark labs you’ll be doing in this course, you’ll be running various network applications in different scenarios using your own computer (or you can borrow a friends; let me know if you don’t have access to a computer where you can install/run Wireshark). You’ll observe the network protocols in your computer “in action,” interacting and exchanging messages with protocol entities executing elsewhere in the Internet. Thus, you and your computer will be an integral part of these “live” labs. You’ll observe, and you’ll learn, by doing.

In this first Wireshark lab, you’ll get acquainted with Wireshark, and make some simple packet captures and observations.

The basic tool for observing the messages exchanged between executing protocol entities is called a packet sniffer. As the name suggests, a packet sniffer captures (“sniffs”) messages being sent/received from/by your computer; it will also typically store and/or display the contents of the various protocol fields in these captured messages. A packet sniffer itself is passive. It observes messages being sent and received by applications and protocols running on your computer, but never sends packets itself. Similarly, received packets are never explicitly addressed to the packet sniffer. Instead, a packet sniffer receives a copy of packets that are sent/received from/by application and protocols executing on your machine.

Figure 1 shows the structure of a packet sniffer. At the right of Figure 1 are the protocols (in this case, Internet protocols) and applications (such as a web browser or ftp client) that normally run on your computer. The packet sniffer, shown within the dashed rectangle in Figure 1 is an addition to the usual software in your computer, and consists of two parts. The packet capture library receives a copy of every link-layer frame that is sent from or received by your computer. Messages exchanged by higher layer protocols such as HTTP, FTP, TCP, UDP, DNS, or IP all are eventually encapsulated in link-layer frames that are transmitted over physical media such as an Ethernet cable. In Figure 1, the assumed physical media is an Ethernet, and so all upper-layer protocols are eventually encapsulated within an Ethernet frame. Capturing all link-layer frames thus gives you all messages sent/received from/by all protocols and applications executing in your computer.


The second component of a packet sniffer is the packet analyzer, which displays the contents of all fields within a protocol message. In order to do so, the packet analyzer must “understand” the structure of all messages exchanged by protocols. For example, suppose we are interested in displaying the various fields in messages exchanged by the HTTP protocol in Figure 1. The packet analyzer understands the format of Ethernet frames, and so can identify the IP datagram within an Ethernet frame. It also understands the IP datagram format, so that it can extract the TCP segment within the IP datagram. Finally, it understands the TCP segment structure, so it can extract the HTTP message contained in the TCP segment. Finally, it understands the HTTP protocol and so, for example, knows that the first bytes of an HTTP message will contain the string “GET,” “POST,” or “HEAD,” as shown in Figure 2.8 in the text.
We will be using the Wireshark packet sniffer [] for these labs, allowing us to display the contents of messages being sent/received from/by protocols at different levels of the protocol stack. (Technically speaking, Wireshark is a packet analyzer that uses a packet capture library in your computer). Wireshark is a free network protocol analyzer that runs on Windows, Linux/Unix, and Mac computers. It’s an ideal packet analyzer for our labs – it is stable, has a large user base and well-documented support that includes a user-guide (, man pages (, and a detailed FAQ (, rich functionality that includes the capability to analyze hundreds of protocols, and a well-designed user interface. It operates in computers using Ethernet, serial (PPP and SLIP), 802.11 wireless LANs, and many other link-layer technologies (if the OS on which it's running allows Wireshark to do so).

Getting Wireshark

In order to run Wireshark, you will need to have access to a computer that supports both Wireshark and the libpcap or WinPCap packet capture library. The libpcap software will be installed for you, if it is not installed within your operating system, when you install Wireshark. See for a list of supported operating systems and download sites

Download and install the Wireshark software: • Go to and download and install the Wireshark binary for your computer.
The Wireshark FAQ has a number of helpful hints and interesting tidbits of information, particularly if you have trouble installing or running Wireshark.

Running Wireshark

When you run the Wireshark program, you’ll get a startup screen, as shown below:

Figure 2: Initial Wireshark Screen

Take a look at the upper left hand side of the screen – you’ll see an “Interface list”. This is the list of network interfaces on your computer. Once you choose an interface, Wireshark will capture all packets on that interface. In the example above, there is an Ethernet interface (Gigabit network Connection) and a wireless interface (“Microsoft”).

If you click on one of these interfaces to start packet capture (i.e., for Wireshark to begin capturing all packets being sent to/from that interface), a screen like the one below will be displayed, showing information about the packets being captured. Once you start packet capture, you can stop it by using the Capture pull down menu and selecting Stop.

The Wireshark interface has five major components: • The command menus are standard pulldown menus located at the top of the window. Of interest to us now are the File and Capture menus. The File menu allows you to save captured packet data or open a file containing previously captured packet data, and exit the Wireshark application. The Capture menu allows you to begin packet capture. • The packet-listing window displays a one-line summary for each packet captured, including the packet number (assigned by Wireshark; this is not a packet number contained in any protocol’s header), the time at which the packet was captured, the packet’s source and destination addresses, the protocol type, and protocol-specific information contained in the packet. The packet listing can be sorted according to any of these categories by clicking on a column name. The protocol type field lists the highest-level protocol that sent or received this packet, i.e., the protocol that is the source or ultimate sink for this packet. • The packet-header details window provides details about the packet selected (highlighted) in the packet-listing window. (To select a packet in the packet-listing window, place the cursor over the packet’s one-line summary in the packet-listing window and click with the left mouse button.). These details include information about the Ethernet frame (assuming the packet was sent/received over an Ethernet interface) and IP datagram that contains this packet. The amount of Ethernet and IP-layer detail displayed can be expanded or minimized by clicking on the plus minus boxes to the left of the Ethernet frame or IP datagram line in the packet details window. If the packet has been carried over TCP or UDP, TCP or UDP details will also be displayed, which can similarly be expanded or minimized. Finally, details about the highest-level protocol that sent or received this packet are also provided. • The packet-contents window displays the entire contents of the captured frame, in both ASCII and hexadecimal format. • Towards the top of the Wireshark graphical user interface, is the packet display filter field, into which a protocol name or other information can be entered in order to filter the information displayed in the packet-listing window (and hence the packet-header and packet-contents windows). In the example below, we’ll use the packet-display filter field to have Wireshark hide (not display) packets except those that correspond to HTTP messages. %翻译

Taking Wireshark for a Test Run

The best way to learn about any new piece of software is to try it out! We’ll assume that your computer is connected to the Internet via a wired Ethernet interface. Indeed, I recommend that you do this first lab on a computer that has a wired Ethernet connection, rather than just a wireless connection. Do the following

1. Start up your favorite web browser, which will display your selected homepage.

2. Start up the Wireshark software. You will initially see a window similar to that shown in Figure 2. Wireshark has not yet begun capturing packets.

3. To begin packet capture, select the Capture pull down menu and select Interfaces. This will cause the “Wireshark: Capture Interfaces” window to be displayed, as shown in Figure 4.

[pic] Figure 4: Wireshark Capture Interface Window

4. You’ll see a list of the interfaces on your computer as well as a count of the packets that have been observed on that interface so far. Click on Start for the interface on which you want to begin packet capture (in the case, the Gigabit network Connection). Packet capture will now begin - Wireshark is now capturing all packets being sent/received from/by your computer!

5. Once you begin packet capture, a window similar to that shown in Figure 3 will appear. This window shows the packets being captured. By selecting Capture pulldown menu and selecting Stop, you can stop packet capture. But don’t stop packet capture yet. Let’s capture some interesting packets first. To do so, we’ll need to generate some network traffic. Let’s do so using a web browser, which will use the HTTP protocol that we will study in detail in class to download content from a website.

6. While Wireshark is running, enter the URL: and have that page displayed in your browser. In order to display this page, your browser will contact the HTTP server at and exchange HTTP messages with the server in order to download this page, as discussed in section 2.2 of the text. The Ethernet frames containing these HTTP messages (as well as all other frames passing through your Ethernet adapter) will be captured by Wireshark.

7. After your browser has displayed the INTRO-wireshark-file1.html page (it is a simple one line of congratulations), stop Wireshark packet capture by selecting stop in the Wireshark capture window. The main Wireshark window should now look similar to Figure 3. You now have live packet data that contains all protocol messages exchanged between your computer and other network entities! The HTTP message exchanges with the web server should appear somewhere in the listing of packets captured. But there will be many other types of packets displayed as well (see, e.g., the many different protocol types shown in the Protocol column in Figure 3). Even though the only action you took was to download a web page, there were evidently many other protocols running on your computer that are unseen by the user. We’ll learn much more about these protocols as we progress through the text! For now, you should just be aware that there is often much more going on than “meet’s the eye”!

8. Type in “http” (without the quotes, and in lower case – all protocol names are in lower case in Wireshark) into the display filter specification window at the top of the main Wireshark window. Then select Apply (to the right of where you entered “http”). This will cause only HTTP message to be displayed in the packet-listing window.

9. Find the HTTP GET message that was sent from your computer to the HTTP server. (Look for an HTTP GET message in the “listing of captured packets” portion of the Wireshark window (see Figure 3) that shows “GET” followed by the URL that you entered. When you select the HTTP GET message, the Ethernet frame, IP datagram, TCP segment, and HTTP message header information will be displayed in the packet-header window[1]. By clicking on ‘+’ and ‘-‘ right-pointing and down-pointing arrowheads to the left side of the packet details window, minimize the amount of Frame, Ethernet, Internet Protocol, and Transmission Control Protocol information displayed. Maximize the amount information displayed about the HTTP protocol. Your Wireshark display should now look roughly as shown in Figure 5. (Note, in particular, the minimized amount of protocol information for all protocols except HTTP, and the maximized amount of protocol information for HTTP in the packet-header window).

10. Exit Wireshark

Congratulations! You’ve now completed the first lab.

Figure 5: Wireshark window after step 9
What to hand in

The goal of this first lab was primarily to introduce you to Wireshark. The following questions will demonstrate that you’ve been able to get Wireshark up and running, and have explored some of its capabilities. Answer the following questions, based on your Wireshark experimentation:

1. List 3 different protocols that appear in the protocol column in the unfiltered packet-listing window in step 7 above. 2. How long did it take from when the HTTP GET message was sent until the HTTP OK reply was received? (By default, the value of the Time column in the packet-listing window is the amount of time, in seconds, since Wireshark tracing began. To display the Time field in time-of-day format, select the Wireshark View pull down menu, then select Time Display Format, then select Time-of-day.) 3. What is the Internet address of the (also known as What is the Internet address of your computer? 4. Print the two HTTP messages (GET and OK) referred to in question 2 above. To do so, select Print from the Wireshark File command menu, and select the “Selected Packet Only” and “Print as displayed” radial buttons, and then click OK.

[1] Recall that the HTTP GET message that is sent to the web server is contained within a TCP segment, which is contained (encapsulated) in an IP datagram, which is encapsulated in an Ethernet frame. If this process of encapsulation isn’t quite clear yet, review section 1.5 in the text…...

Similar Documents

Free Essay

Melp Final

... 2 DSK SUPPORT TOOLS 1. TI’s DSP starter kit (DSK). The DSK package includes: (a) Code Composer Studio (CCS), which provides the necessary software support tools. CCS provides an integrated development environment (IDE), bringing together the C compiler, assembler, linker, debugger, and so on. (b) A board, shown in Figure 1.1, that contains the TMS320C6416 (C6416) fixed-point digital signal processor as well as a 32-bit stereo codec for input and output (I/O) support. (c) A universal synchronous bus (USB) cable that connects the DSK board to a PC. (d) A 5V power supply for the DSK board. TI C6416 DSK Overview: The digital signal processor is considered to be the heart of the main system. It is designed to perform the beamforming as well as the source localization task. The processor used is a Texas Instruments C6416 DSP which operates at clock speed of 1 GHz. The processor comes preinstalled onto a DSP Starter Kit by Spectrum Digital, called as the TMS320C6416T DSK board. The DSK board makes it easier to interface the DSP with external peripherals, analogue to digital converters, external memory units, power supplies, and is controlled using the CCS Studio software (Texas Instruments) through a USB interface from a PC running on normal Microsoft Windows environment. The CCS Studio software comes with a C compiler and an assembler which, helps in programming and controlling the Digital Signal Processor from the pc over the USB interface. The DSK board also......

Words: 9574 - Pages: 39

Free Essay


...ARQ and frequency reuse. However, the former two will be elaborated in detail under this section and the later (frequency reuse) will be discussed in the next chapter. 2.4.1 Advanced Antenna Systems IEEE 802.16 standard provides the support for implementing advanced multi-antenna solutions which improve the system performance. We are deploying AAS to get gain in the capacity of the system and more bandwidth efficiency. The varieties of multiple antennas mentioned in AAS are as follows: Transmit diversity: For transmit diversity, there may be two or more antennas on the transmitter and receiver sides. A numbers of space time block coding schemes can be employed to achieve transmit diversity for the downlink. Beamforming: Beamforming ensures better capacity, more coverage and greater reliability in the network.The antenna beam can be creat in the direction of desired user and block the interferers. Spatial Multiplexing: Different streams are transmitted on multiple antennas in spatial multiplexing. 2.4.2 Hybrid ARQ Hybrid ARQ is the combination of Forward Error Correction (FEC) and ARQ. It is implemented at the physical layer with FEC. It improves the link performance when compared with traditional ARQ at the cost of complexity. The FEC coder encoded the block of data along with the CRC code before transmission. If the decoder fails to decode the received block, the retransmission is requested. The received block is combined with the......

Words: 15898 - Pages: 64

Free Essay

Lte Complete Tutorial

...improve the data throughput available on a given channel with its defined bandwidth. By using multiple antennas at the transmitter and receiver along with some complex digital signal processing, MIMO technology enables the system to set up multiple data streams on the same channel, thereby increasing the data capacity of a channel. Click on the link for a MIMO tutorial For LTE Advanced, the use of MIMO is likely to involve further and more advanced techniques with additional antennas in the matrix to enable additional paths to be sued, although as the number of antennas increases, the overhead increases and the return per additional path is less. In additional to the numbers of antennas increasing, it is likely that techniques such as beamforming may be used to enable the antenna coverage to be focused where it is needed. With data rates rising well above what was previously available, it will be necessary to ensure that the core network is updated to meet the increasing requirements. It is therefore necessary to further improve the system architecture. These and other technologies will be used with LTE Advanced to provide the very high data rates that are being sought along with the other performance characteristics that are needed. . . . . . . . . . . LTE CA: Carrier Aggregation Tutorial - 4G LTE Advanced CA, carrier aggregation or channel aggregation enables multiple LTE carriers to be used together to provide the high data rates required for 4G LTE......

Words: 18462 - Pages: 74

Free Essay

Hyper Geomatric

...series, Math. Comp. 19 (1965), 297–301. MR MR0178586 (31 #2843) 4. J. Demmel and P. Koev, Accurate and efficient evaluation of Schur and Jack functions, Math. Comp. 75 (2006), 223–239. 5. Persi Diaconis and Daniel Rockmore, Efficient computation of the Fourier transform on finite groups, J. Amer. Math. Soc. 3 (1990), no. 2, 297–332. MR MR1030655 (92g:20024) 6. H. Gao, P.J. Smith, and M.V. Clark, Theoretical reliability of MMSE linear diversity combining in Rayleigh-fading additive interference channels, IEEE Transactions on Communications 46 (1998), 666– 672. 7. A.J. Grant, Performance analysis of transmit beamforming, IEEE Transactions on Communications 53 (2005), 738–744. 8. R. Guti´errez, J. Rodriguez, and A. J. S´aez, Approximation of hypergeometric functions with matricial argument through their development in series of zonal polynomials, Electron. Trans. Numer. Anal. 11 (2000), 121–130. 9. G. H. Hardy, Ramanujan: Twelve lectures on subjects suggested by his life and work., AMS Chelsea, New York, 1999. 10. M. Kang and M.-S. Alouini, Largest eigenvalue of complex Wishart matrices and performance analysis of MIMO MRC systems, IEEE Journal on Selected Areas in Communications 21 (2003), no. 3, 418–431. ......

Words: 4950 - Pages: 20

Premium Essay

802.11ac Migration Guide

...streams. Aruba Networks, Inc. 5 802.11ac Aruba Migration Guide Downlink multi-user MIMO Thus far, all 802.11 communication has been point-to-point (one-to-one) or broadcast (one-to-all). With future versions of 802.11ac, a new feature allows an AP to transmit different streams to several targeted clients simultaneously. Pros of 802.11ac • The maximum speeds/bandwidth supported by 802.11ac will vary from 433 Mbps to 6.93 Gbps. • A single 802.11ac radio can accommodate more users/Wi-Fi devices than previous standards (802.11a/b/g/n). • 802.11ac will support higher data rate over longer distances. This is due to the more aggressive error correction codes supported by 802.11ac as well as a quieter RF environment. • 802.11ac uses beamforming to improve SNR. This results in better wireless throughput. • 802.11ac uses 256-QAM that provides a 33% increase in throughput over 64-QAM used in 802.11n. • Future versions of 802.11ac will use multi-user MIMO (MU-MIMO) that allows APs to transmit single/multiple streams to multiple clients at the same time. This allows for better efficiencies for where a large number of lowconfiguration Wi-Fi devices, such as smartphones, need to connect. • Since 802.11ac operates in the 5-GHz spectrum, there is lower interference from other wireless devices. There are more non-overlapping channels (23 20-MHz channels) in 5 GHz, which provides for greater design flexibility. Cons of 802.11ac • Existing 802.11n APs cannot be upgraded to......

Words: 3787 - Pages: 16

Free Essay

Dsp Lessons

...Psychoacoustics. Adaptive Differential Pulse Code Modulation (ADPCM): ADPCM is a family of speech compression and decompression algorithms which use adaptive quantizers and adaptive predictors to compress data (usually speech) for transmission. The CCITT standard of ADPCM allows an analog voice conversation sampled at 8kHz to be carried within a 32kbits/second digital channel . Three or four bits are used to describe each sample which represent the difference between two adjacent samples. See also Differential Pulse Code Modulation (ADPCM), Delta Modulation, Continuously Variable Slope Delta Modulation (CVSD), G.721. Adaptive Beamformer: A spatial filter (beamformer) that has time-varying, data dependent (i.e., adaptive) weights. See also Beamforming. Adaptive Equalisation: If the effects of a signal being passed through a particular system are to be “removed” then this is equalisation. See Equalisation. Adaptive Filter: The generic adaptive filter can be represented as: d( k) x( k ) Adaptive Filter, w(k) y(k) + e( k) − Adaptive Algorithm y ( k ) = Filter { x ( k ), w ( k ) } w ( k + 1 ) = w ( k ) + e ( k )f { d ( ( k ), x ( k ) ) } In the generic adaptive filter architecture the aim can intuitively be described as being to adapt the impulse response of the digital filter such that the input signal x ( k ) is filtered to produce y ( k ) which when subtracted from desired signal d ( k ) , will minimize the power of the error signal e ( k ) . The adaptive......

Words: 73093 - Pages: 293

Free Essay

Analysis of Physical Parameters Influencing Beam Pattern of Uniform Linear Array of Antennas

...5 2 Linear Array of Antennas 2.1 Design of Array Antennas………………………….……………………………6 2.2 Uniform Linear Array of Antennas …………………..…………………………6 2.3 Broadside vs. end fire arrays……………………….……………………………7 2.4 Array Manifold Vector………………………………..…………………………7 2.5 Array Pattern…………………………………………………….………………9 2.6 Beam pattern parameters………………………….……………………………10 2.6.1 Main Lobe………………...…………………………………………10 2.6.2 Side lobe…………………………………………….……………….10 2.6.3 Grating Lobes……………….…………………….…………………11 2.6.4 Nulls…………………………………………………………………12 2.6.5 Beam width…………………………………….……………………13 2.6.6 Directivity and Gain……………………………...…………………13 3 Beamforming and Factors Effecting Uniform Linear Array of Antennas 3.1 Beamforming ………………………………………………………………..…14 3.1.1 Adaptive Beamforming………………………………………………14 3.2 Factors effecting beam pattern of linear array…………………………………15 3.2.1 Effect of number of elements……………………………………...…15 3.2.2 Effect of spacing between elements………………………………….17 4 Weighting Techniques 4.1 Uniform weightings……………………………………………………………21 4.2 Cosine weightings……………………………………………………………...22 4.3 Hamming weightings…………………………………………………………..24 4.4 Blackman weightings…………………………………………………………..25 4.5 Comparison of results…………………………………………………………26 5 Conclusions and Future Work 5.1 Conclusion………………………………………………………………..…….29 5.2 Future works……………………………………………………………..……..29 6 ......

Words: 6048 - Pages: 25

Premium Essay


...Fix computers es. With speeds up to AC900 Mbps (N300 +AC565), wireless-AC provides gigabit Wi-Fi speeds that allow content to download faster. Wireless-AC makes it possible for you to stream shows on your HDTV while family members download music or other files–without interruption due to a slow network connection. The AC900 includes a USB 3.0 port and four gigabit ports to let you connect multiple devices, allowing you to quickly print, share, and store content across your network. The Linksys AC900 Smart Wi-Fi router features beamforming, an innovative technology that optimizes the wireless signal strength between your connected devices and Linksys router. Beamforming enables the router to identify and connect directly with other devices, rather than simply sending out wireless signals in a general direction. The result is faster network speeds, better wireless range, and reduced interference from other devices. It also helps extend the battery life of connected devices and reduce their power consumption because data is transferred more quickly. Manage Your Home Network Remotely with Linksys Smart Wi-Fi With Linksys Smart Wi-Fi, you can access and control your home network from wherever you are using your smartphone, tablet, or computer. For example, you can set parental controls to restrict Internet access during certain times of the day and create unique, secure Wi-Fi passwords for your guests. You can also monitor activity on your home network, add new devices...

Words: 448 - Pages: 2

Premium Essay

Celular Networks Small Cells

...using Mobile data offloading as a more efficient use of radio spectrum. Small cells are a vital element to 3G data off-loading, and many mobile network operators see small cells as vital to managing LTE Advanced spectrum more efficiently compared to using just macrocells. Small cells can be used to provide in-building and outdoor wireless service. Mobile operators use small cells to extend their service coverage and/or increase network capacity. With small cells, mobile operators can offload traffic as much as 80% during peak times. Small cells cover Femtocells, Picocells, and Microcells. Small cell networks can also be realized by means of distributed radio technology consisting of centralized baseband units and remote radio heads. Beamforming technology (focusing a radio signal on a very specific area) can be utilized to further enhance or focus small cell coverage. A common factor in all these approaches to small cells is that they are centrally managed by mobile network operators. Small cells provide a small radio footprint, which can range from 10 meters within urban and in-building locations to 2 km for a rural location. Picocells and microcells can also have a range of a few hundred meters to a few kilometers, but they differ from femtocells in that they do not always have self-organizing and self-management capabilities. Small cells are available for a wide range of air interfaces including GSM, CDMA2000, TD-SCDMA, W-CDMA, LTE and WiMax. In 3GPP terminology, a......

Words: 4350 - Pages: 18

Premium Essay

Green Radio: Radio Techniques to Enable Energy Efficient Wireless Networks

...MANAGEMENT It is difficult to cancel the effect of interference where the same spectrum is shared by multiple base stations. The effect of interference increases as the users approach closer to the boundary region between any two cells. This leads to SINR and rate is reduced. Green Radio is focusing on developing efficient scheme to reduce the effect of interference. If interference can be decreased at the mobile terminals then it will allow the base stations to decrease the wireless transmission energy without any effect on the SINR of the wireless link. There are two methods, they are receiver interference cancellation and distributed antenna systems. In Distributed Antenna System interference is controlled on the cell edge by coordinated beamforming at all the base stations which are participating. There are three schemes for coordinating downlink beam-forming: 1) One or more base stations are allocated to the users. 2) Using multiple antenna beam-forming and coherent users’ end combining all the users are served with multiple base stations. 3) The base station with the highest SINR is served to the user and other base stations don’t transmit signal energy towards that user. Scheme 3 is preferable over schemes 1 and 2 in practical implementation, as it requires much less channel data about the users that is exchanged between the base stations with less energy usage. As the number of transmission antennas increase more transmission energy is required. When there is no......

Words: 4184 - Pages: 17

Free Essay

744 Commerce Control List

...m and having transducers with any of the following: (1) Dynamic compensation for pressure; or (2) Incorporating other than lead zirconate titanate as the transduction element; (ii) 6A001.a.1.e. (iii) 6A001.a.2.a.1, a.2.a.2, a.2.a.3, a.2.a.5, and a.2.a.6. (iv) 6A001.a.2.b. (v) 6A001.a.2.c – Processing equipment, specially designed for real time application with towed acoustic hydrophone arrays, having “user accessible programmability” and time or frequency domain processing and correlation, including spectral analysis, digital filtering and beamforming using Fast Fourier or other transforms or processes. (vi) 6A001.a.2.d. (vii) 6A001.a.2.e. (viii) 6A001.a.2.f – Processing equipment, specially designed for real time application with bottom or bay cable systems, having “user accessible programmability” and time or frequency domain processing and correlation, including spectral analysis, digital filtering and beamforming using Fast Fourier or other transforms or processes. (ix) 6A002.a.1.a, a.1.b, and a.1.c. (x) 6A002.a.1.d. (xi) 6A002.a.2.a – Image intensifier tubes having all of the following: Export Administration Regulations Bureau of Industry and Security May 21, 2015 Commerce Control List Sensitive List Supplement No. 6 to Part 774—page 6 (A) A peak response in the wavelength range exceeding 400 nm but not exceeding 1,050 nm; (B) Electron image amplification using any of the following: (1) A microchannel plate for electron image......

Words: 7650 - Pages: 31

Free Essay


...more spatial streams (radio signals) in the same channel between two or more different antennas on access point and wireless hosts. b) What is the main benefit of MIMO? What is its other benefit? Greater transmission speed & greater transmission distance. 20. a) What is beamforming? Having multiple antennas and changing the phase of waves coming from different antennas, an access point can focus signals toward individual hosts instead of broadcasting them,] b) Distinguish between MIMO and multiuser MIMO. Multiuser MIMO is the possibility of simultaneously transmission in a single channel by multiple devices that are using a single access point as oppose to just one on MIMO. Beamforming can also bring multiuser MIMO, which is the possibility of simultaneous transmission in a single channel by multiple devices that are using a single access point. The 802.11n standard specified multiuser MIMO, but it did not specify a single multiuser MIMO technology. This led to a great deal of market confusion, and multiuser MIMO did not become popular with 802.11n. With 802.11ac, the Technical Group 802.11ac avoided market confusion by specifying a single multiuser MIMO technique. Beamforming is likely to be common in 802.11ac products. 21. a) Distinguish between rated speed, aggregate throughput, and individual throughput. Rated speed is the number of bits that the host or access point will transmit per second. Access point throughput is aggregate......

Words: 5126 - Pages: 21

Free Essay

Software Implementation Paper photos and any other documents needed to be stored like spreadsheets. | RDA005, RDA014, RDA016, RDA017, | SAPPHIRE 100381OCL Radeon R9 390X 8GB 512-Bit GDDR5 PCI Express 3.0 2.2 Slot, ATX Tri-X OC Version (UEFI) Video Card | * 2816 Stream Processors * 8GB 512-Bit GDDR5 * PCI Express 3.0 | * This will enhance digital photos by being able to run high-end software * Allow to run multi-programs with high-end multi-media requirements. * Enhance video streaming and editing of video files by running high-end software * Enhance photos and digital media with top end software capability | RDA013, RDA014, RDA015, RDA015, RDA016, RDA017 | Creative Sound Blaster Z PCIe 116dB SNR Gaming Sound Card with 600ohm Headphone Amp and Beamforming Microphone | * PCI Express x1 5.1 Channels * TOSLink Optical Input and Output * Sound Core3D Processor * Beam-forming Microphone | * This component you will have the state of the line sound blaster software to manage audio files with video files. | RDA013 | Dell P2314T Black 23" USB Mastouch Projected Capacitive Touchscreen Monitor IPS 270 cd/m2 8000000:1 (1000:1) | * 1920 x 1080 * 8000000:1 (1000:1) * D-Sub USB * 178° (H) / 178° (V) | * This component allows the user to see every function of what is going on in the system unit. Therefore this component is very important and can be related to all attributes needed. * The high refresh rate allows for quality images and videos. | RDA001, RDA002,......

Words: 1552 - Pages: 7

Premium Essay


...Frequency Re-Use 4.2.3 Channel Estimation 4.2.4 Cyclic Prefix Insertion 4.2.5 Use of the Frequency Domain 4.2.6 Choice of Sub-Carrier Spacing Single Carrier Frequency Division Multiple Access 4.3.1 Power Variations from OFDMA 4.3.2 Block Diagram of SC-FDMA References 66 66 67 68 69 70 72 72 72 73 76 Multiple Antenna Techniques Diversity Processing 5.1.1 Receive Diversity 5.1.2 Closed Loop Transmit Diversity 5.1.3 Open Loop Transmit Diversity Spatial Multiplexing 5.2.1 Principles of Operation 5.2.2 Open Loop Spatial Multiplexing 5.2.3 Closed Loop Spatial Multiplexing 5.2.4 Matrix Representation 5.2.5 Implementation Issues 5.2.6 Multiple User MIMO Beamforming 5.3.1 Principles of Operation 5.3.2 Beam Steering 5.3.3 Dual Layer Beamforming 5.3.4 Downlink Multiple User MIMO Revisited References 77 77 77 78 79 80 80 82 84 85 88 88 90 90 91 92 93 94 Architecture of the LTE Air Interface Air Interface Protocol Stack Logical, Transport and Physical Channels 6.2.1 Logical Channels 6.2.2 Transport Channels 6.2.3 Physical Data Channels 6.2.4 Control Information 6.2.5 Physical Control Channels 6.2.6 Physical Signals 6.2.7 Information Flows The Resource Grid 6.3.1 Slot Structure 6.3.2 Frame Structure 6.3.3 Uplink Timing Advance 6.3.4 Resource Grid Structure 6.3.5 Bandwidth......

Words: 124044 - Pages: 497

Free Essay


...demodulation is performed by minimizing the second term. This form suggests an iterative approach, where the signal associated with each transmitter, in turn, is considered to be user A and is demodulated by minimizing Ins − PTX PZ X . If TA is a row vector, such that nA = 1, then the sec114 L INCOLN LABORATORY JOURNAL VOLUME 15, NUMBER 1, 2005 ns (50) , where ˆˆ w A = R −1 H A , X 1 1 ⊥ ˆ R X ≡ Z X Z † = ZPTB Z † , X ns ns † † ˆ H A ≡ Z X TX (TX TX )−1 ⊥ | ZPT Z † |−ns . (47) ⊥ Z PT Z † ⊥† w † ZPTB TA A = 1− assuming that R is not rank deficient. Using these results, the ML statistic for estimating T is given by − ns nR † w † Z X TX A , ns = 1− (51) ⊥† ⊥† = ZPTB TA (TA PTB TA )−1 . The nR × 1 vector wA contains the receive beamforming ˆ weights, R X is the interference-mitigated signal-plusˆ noise covariance matrix estimate, and H A is the channel estimate associated with TA . It is worth noting that ˆ ˆ the form for H A is simply the column of H , given in Equation 43, associated with TA . ˆ H = ZT † (T T † )−1 =  T T†  † †  A A Z  TA TB     † T T BA ≡ M 11 ,  † †  Z  TA TB   †    M1,2  † TA TB   −1  † TBTB   M1,2  −1   M2,2   (52) †† = Z  TA TB      †  (M11 − M1,2 M−,12 M1,2 )−1  , 2 ⋅ . −1 † −1 † −1 − M2,2 M1,2 (M11 − M1,2 M2,2 M1,2 )   , By focusing on the first column and substituting in for ˆ M1,1, M1,2, and M2,2, we can find H A . † † † † † ˆ H A = ZTA (TA TA − TA TB [TB TB ]−1 TB TA......

Words: 16967 - Pages: 68

once upon a time | biglietti concerto baglioni bari 6 novembre | épisode 8 streaming Too Far Gone