M. B. Pursley, "The Role of Spread Spectrum in Packet Radio Networks," Proceedings of IEEE, (1) pp. 116-34, January 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....applies to two different types of networks. The first is the cellular network where the base station allocates channels using some form of demand assignment strategies. The second type is the ad hoc network that employs code division multiple access (CDMA) and receiver based transmission protocol [15]. In such a network, a transmitting node wishing to communicate with a receiving node must know and use codes assigned to the receiver, and a request acknowledge process may be necessary. The MAC considered here is similar to the widely used RTS CTS protocol except that the request and ....

M. B. Pursley. The Role of Spread Spectrum in Packet Radio Networks. Processings of The IEEE, 75(1):116-134, Jan. 1987.

....site of their sensing application is reached a semi permanent stationary configuration is adopted for the purpose of gathering information. In the area of general ad hoc networks as well as sensor webs, research has focused on routing [3] medium access control (MAC) 4] 5] and physical layer [6]. 7] and [8] are protocol suites specifically designed for sensor webs. Theoretical results regarding capacity of general static ad hoc networks first appeared in [9] Also relevant to our research is the so called packet routing problem which consists in moving packets of data from one location ....

M. Pursley, "The role of spread spectrum in packet radio networks.," Proceedings of the IEEE, Jan. 1987.

....transmissions between mobiles and base stations. In the ad hoc networking paradigm, links may correspond to single hop transmissions between laptop computers (or other mobile and or static infrastructure) In FDMA systems, the channels are nonoverlapping frequency bands. In spread spectrum systems [20], the whole spectrum can be viewed as a single channel and interference basically reflects cross correlation effects between codes in CDMA transmission. Generally speaking, the transmission quality (bit error rate) of a network link is a decreasing function of the SIR at its receiver node. Given ....

M. B. Pursley, "The role of spread spectrum in packet radio networks," Proc. IEEE, vol. 75, Jan. 1987.

....sequence spread spectrum radios are used, which are the type of radios found in Metricom and Wavelan modems. These devices are susceptible to near far interference, which occurs when the receiver picks up interference from another transmitter that has a stronger signal than the desired signal [15]. Both the link from the base station to the mobile unit (forward link ) and from the mobile unit to the base station (reverse link) are affected, though the reverse link is usually more susceptible [19] In general, power control methods by their very nature should reduce the energy needed by a ....

M. B. Pursley. The role of spread spectrum in packet radio networks. In Proceedings of the IEEE, pages 116--134, 1985.

....Two nodes wishing to communicate can do so directly, or else by using nodes lying in between them to route their packets. In the past, research on ad hoc networks has mainly focused on the routing [4] and medium access control (MAC) 1] problems, and on issues regarding the physical layer [3]. The problem of determining theoretical upper bounds on the performance of ad hoc networks was not attacked until recently [2] The authors of [2] studied the capacity of ad hoc networks in the limit of a large number of nodes. Here we # Work supported by the O#ce of Naval Research (ONR) grant ....

M. Pursley. The role of spread spectrum in packet radio networks. Proceedings of the IEEE, January 1987.

....Two nodes wishing to communicate can do so directly, or else by using nodes lying in between them to route their packets. In the past, research on ad hoc networks has mainly focused on the routing [4] and medium access control (MAC) 1] problems, and on issues regarding the physical layer [3]. The problem of determining theoretical upper bounds on the performance of ad hoc networks was not attacked until recently [2] The authors of [2] studied the capacity of ad hoc networks in the limit of a large number of nodes. Here we extend the results of [2] to a 3 dimensional topology, and ....

M. Pursley. The role of spread spectrum in packet radio networks. Proceedings of the IEEE, January 1987.

.... ratio for the required level of performance [9] This approach provides multiple access capability, named code division multiple access (CDMA) by allowing multiple receivers to simultaneously receive packets from different transmitters when the communications overlap in time and space domains [10]. The code assignment scheme determines the spreading codes to be used in an ad hoc wireless network. There are four basic types of code assignment [8,11] a) Common code: All nodes are assigned the same common code. The addressing information is placed at the packet header to identify the ....

....2 receives the CTS and sends the data packet to node 1 on Ct2 code. Since the RTS, the CTS and the data packets are sent on different codes, they only increase the interference level at the neighboring nodes and may not cause any collision. The interference rejection capability of spread spectrum [10] could avoid the hidden terminal and the exposed terminal problems. Similar to the MACA C T protocol, the data packets are sent on a transmitter based code; thus, multiple transmitters can send data packets successfully to different receivers. Fig. 6 illustrates a situation where an intruder ....

M. B. Pursley, "The role of spread-spectrum in packet radio networks," Proc. IEEE, Vol. 75, No. 1, Jan. 1987, pp. 116-143.

....review of this paper and approving it for publication was Prof. Michail K. Tsatsanis. The authors are with the School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853 (e mail: ltong ee.cornell.edu) Publisher Item Identifier S 1053 587X(00)07678 9. mission protocols [13]. In general, spread spectrum transmission protocols can be classified into three major modes [15] 1) Transmitter oriented spread spectrum transmission protocol With this protocol, each user is assigned a unique transmitting code. If the transmitter based codes used by different users are ....

M. B. Pursley, "The role of spread spectrum in packet radio networks," Proc. IEEE, vol. 75, pp. 116--134, Jan. 1987.

....spectrum. The solution to this issue depends on several aspects of system design [6] the most noticeable of which is the spreadspectrum transmission protocol. A transmission protocol is the rule that governs the selection of spreading sequence or code to use in the transmission of a packet [9]. If two MHs within a cell use the same code to transmit a packet at the same time, the packet will be lost due to collision. There are mainly three transmission protocols, viz. transmitter oriented, receiver oriented and common code protocols. In the first protocol, each MH has its own unique ....

....the receiver which listens to this code can recover the bits from the symbols; other receivers perceive them as noise. It is important that two MHs should use different codes for transmission at the same time; otherwise, the receiver cannot distinguish them. For simplicity, the effect of capture [9] is not considered in this paper. Even if a bit transmitted by a MH is spread with a code different from any other code used at the same time, it may still be corrupted because the bits simultaneously transmitted by other MHs generate some level of noise on the intended receiver. This is called ....

M. B. Pursley, "The role of spread spectrum in packet radio networks," Proceedings of The IEEE, vol. 75, no. 1, pp. 116--134, January 1987.

....Curiously, there is little work reported on this subject. There are many prior examples of MAC protocols for frequencyhopping radios, which are typically based on applying ALOHA or slotted ALOHA using the same hopping sequence for all nodes or sender or receiver oriented code assignments [6, 8]. However, these approaches assume that radios hop frequencies within the same packet frequently to achieve code division multiple access (CDMA) IEEE 802.11 [1] incorporates a convergence layer that makes the characteristics of the physical layer transparent to the MAC protocol. A concrete ....

M. B. Pursley. The role of spread spectrum in packet radio networks. Proceedings of the IEEE, 75(1):116--34, January 1987.

....Curiously, there is little work reported on this subject. There are many prior examples of MAC protocols for frequency hopping radios, which are typically based on applying ALOHA or slotted ALOHA using the same hopping sequence for all nodes or sender or receiveroriented code assignments [7][8]. However, these approaches assume that radios hop frequencies within the same packet frequently to achieve code division multiple access (CDMA) IEEE 802.11[1] incorporates a convergent layer that makes the characteristics of the physical layer transparent to the MAC protocol. A concrete example ....

M. Pursley, "The role of spread spectrum in packet radio networks, "Proceedings of the IEEE, Jan. 1987, vol.75, (no.1):116-34.

....protocols can be classified into two main types, conflict free, and contention based schemes. Conflict free protocols ensure that a transmission will not be interfered by another transmission. This can be done by allocating the channel to the users either statically (e.g. TDMA [48] FDMA and CDMA [43]) or dynamically (e.g. BRAM [10] MSAP [34] On the other hand, in contention based schemes, stations content for the channel on a packet by packet basis (e.g. ALOHA [1] and CSMA [33] Several MAC protocols have been proposed over the past few years that are based on three or four way ....

M. B. Pursley, "The Role of Spread Spectrum in Packet Radio Networks," Proceedings of IEEE, (1) pp. 116-34, January 1987.

.... capable of autonomous operation) and to reliably control (if there system wide dependencies on topology in the slot assignment algorithms) Spread spectrum s anti jam capabilities have long been recognized as a potentially valuable tool for handling interference in packet radio networks (e.g. 7] [12], and [18] Spread spectrum techniques allow the designer to treat, to some extent, interfering signals as if they were random (thermal like) noise. To what extent this is true is discussed in [18] where it is suggested (on page 1109) that 5 dB of additional signal to noise margin more than ....

Michael B. Pursley. The role of spread spectrum in packet radio networks. Proceedings of the IEEE, 75(1):116--134, January 1987.

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M. B. Pursley, "The Role of Spread Spectrum in Packet Radio Networks," Proceedings of IEEE, (1) pp. 116-34, January 1987.

No context found.

M. B. Pursley. The Role of Spread Spectrum in Packet Radio Networks. Proceedings of the IEEE, 75(1):116-134, January 1987.

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M. B. Pursley, "The role of spread-spectrum in packet radio network," Proc. IEEE, Vol. 75, pp. 116-134, Jan 1987.

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M. B. Pursley, "The role of spread spectrum in packet radio networks," Proc. IEEE, vol. 75, pp. 116--134, Jan. 1987.

No context found.

M. B. Pursley. The role of spread-spectrum in packet radio networks. Proceedings of the IEEE, 75(1):116--134, January 1987.

No context found.

M. B. Pursley, "The role of spread spectrum in packet radio networks," Proc. IEEE, vol. 75, pp. 116--134, Jan. 1987.

No context found.

M. B. Pursley, "The role of spread spectrum in packet radio networks, " Proceedings of the IEEE, vol. 75, pp. 116--134, January 1987.

No context found.

. M. Pursley, The role of spread spectrum in packet radio networks, Proc. IEEE, vol.75, pp 116-134, January 1987.

No context found.

. M.B. Pursley, "The role of spread spectrum in packet radio networks," Proc, IEEE, Vol.75, No.1, pp.116-134, January 1987.

No context found.

M. B. Pursley. The Role of Spread Spectrum in Packet Radio Networks. Proceedings of the IEEE, 75(1):116-134, January 1987.

No context found.

Michael B. Pursley. The role of spread spectrum in packet radio networks. Proceedings of the IEEE, 75(1):116--134, January 1987.

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