In wireless networks we have high and time varying packet losses due to the effect of fading. One way to provide communication without effect of fading is to introduce channel coding and network coding in the system operation. Channel coding (redundant symbols/ bits at the physical layer) is to add redundant information into inside the packet to recover errors in the original information. Network coding (redundant packets at the network layer) is to add redundant information across multiple packets. The channel coding can be called as error correction and the latter network coding can be called as erasure correction. Specially, channel coding is a conventional error correction technique it can be used for point-to-point communication …show more content…
Conversely, erasure correction is always used as end-to-end communication. It can be operated on the packet level, and can be used at either link layer, network layer, or application layer. The traditional network coding allows the intermediate nodes along multiple interleaved paths to generate redundant network-coded packets without decoding all original packets in a distributed manner [1], [2], while the redundancy on network layer can also be used for error correction. Here we explain how to use joint network channel coding scheme based on LDPC codes for multiple access relay channel in section I and Section II. We proposed some preliminaries for our proposed schemes of Min-max relay selection algorithm on Section III. We proposed En masse relay selection schemes and detailed explanation about in Section IV. We shown that En masse relay selection schemes achieves significant performance gains compared to min-max selection criterion in Section V. II. NON-BINARY JOINT NETWORK CHANNEL …show more content…
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When there is loss of packet, the sender doesn’t wait for the time out and resends the packets immediately using the mechanism of fast recovery and fast retransmit.
There was a time in our life when going wireless was a dream and was considered highly expensive but then started the era of WIFI. The first outcome of this wireless transmission was IEEE 802.11 standard for wireless data transmission and it progressed as a/b/n with the time. The last stand 802.11n was the real heavyweight and gained a lot of popularity based on its amazing performance. It gave almost 5 times increase in bandwidth using MIMO (Multiple Input Multiple Output) antenna technique. The user experience for 802.11n standard was so good that it was called “end of an Ethernet” at that time. AC standard operates in the 5GHz band with some enhanced physical layer set with the idea of better video communication. It comes with more antennas, wider channels and more spatial stream along with a number of new features to boost throughput and reliability. This new IEEE 802.11ac technology is in reality only an up gradation of physical layer wireless technique used in 802.11n by the use of multiple inputs multiple output (MIMO) antenna technique. Few improvements done in 802.11ac and modified parameters can be studied as following:
My research interest of working with coding theory, information theory, multiple access methods, and adaptive equalization, all match considerably with the research focuses of EECS Berkeley’s faculty. EECS Berkeley has the finest faculty and the most developed research facilities in the World of Electrical Engineering, and more specifically, in the field of wireless & mobile communications.
.... A. (2012). LTE, LTE-advanced, and WiMAX: Towards IMT-advanced networks. Chichester, West Sussex, U.K: Wiley.
Johnson, D., Maltz, D. (1996). Dynamic Source Routing in Ad-hoc Wireless network. Print ISBN: 0 79239697 0
Wireless LANs have expanded greatly and rapidly in recent years. The expansio¬¬¬¬¬n has caused many benefits to the end users but at the same time it has introduced problem of overlapping BSS (Basic Service Set) where BSS (i.e. WLAN cells) is fundamental block of IEEE 802.11 WLAN architecture. OBSS occurs due to two or more unrelated BSSs are used at the same place, at the same time and with the same frequency channel. With the expansion of channel bandwidth to 80 MHz (may be, 160 MHz) in upcoming standards, the OBSS problem is likely to be very severe in the future. This paper examines how OBSS can be harmful to the networks and how it can be avoided using beam forming, distributed coordination across different APs, and power management. At the end, this text explores the effectiveness of the proposed solutions.
... in Wireless Sensor Networks: Current proposal and Future Development, IEEE Xplore, Hong Kong, Oct- 2007.
The sender encodes the information and selects the communication channel through which the message is sent, the receiver receives and decodes the message and
Data that is transmitted can either be in digital form, for example originating from a data sources like computer etc. or it can be in analog form such as a video/audio signal which is then digitized into a bit-stream by using modulation techniques or source coding schemes like data compression and analog to digital conversion. The modern modulation techniques include pulse width and pulse code modulation. The codec equipment helps in carrying out the source coding and decoding work.
throughput by transmitting independent data streams on the different transmit branches simultaneously and at the same carrier frequency.
[7] Theodore S. Rappaport, “Multiple Access Technique for Wireless communications”, Second Edition pp. 451- 463, 1996.
The Key activity of this paper is to avoid the data loss in the network and also providing...
2. M. C. Valenti and N. Correal, “Exploiting Macrodiversity in Dense Multihop Networks and Relay”
When encoding a message, the sender has to begin by deciding what he/she wants to transmit. This decision by the sender is based on what he/she believes about the receivers knowledge and assumptions, along with what additional information he/she wants the receiver to have. It is important for the sender to use symbols that are familiar to the intended receiver. A good way for the sender to improve encoding their message, is to men...
first condition of communication is must sender(encoder) and receiver(decoder) without it we cant communicate.encodeing shows the message has been send and decoding shows message ha been receiving