Gregory J. Pottie, "System Design Choices in Personal Communications," IEEE Personal Communications, pp. 50-67, October 1995.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....out the interference among all channels. This is effective if the number of available channels is large and is very simple to implement and does not require a lot of prior planning in the network. Averaging interference has a poorer performance compared to an algorithm that avoids interference [12]. RND is usually used as the lower bound performance for channel allocation methods. This is because the RND algorithm does not use any current or prior information to allocate a channel. 2.2.1.2 Fixed Channei Allocation Consider a cellular network with uniform traffic (i.e. each cell is the ....

Gregory J. Pottie, "System Design Choices in Personal Communications," IEEE Personal Communications, pp. 50-67, October 1995.

....cellular systems, interference fluctuations are handled by so called interference averaging, e.g. frequency hopping or DS CDMA. This is not possible in DVB T, without a major change of existing hardware. However, that should not be considered as a problem. On the contrary, it was shown by Pottie [11] that interference avoidance by DCA and power reservation can perform a factor 2 to 3 better spectrum efficiency than interference averaging techniques. Interference avoidance by resource reservation requires synchronized and centrally controlled base stations. Centralized resource reservation ....

G. J. Pottie, "System design choices in personal communications," IEEE Personal Commun., Oct. 1995.

....fairness. A challenging research topic is RRM for packet data cellular systems, because of the highly fluctuating nature of the co channel interference. In modern cellular systems, interference fluctuations are handled by interference averaging by spread spectrum. However, it was shown by Pottie [4] that interference avoidance by DCA and power reservation can perform a factor 2 to 3 better spectrum efficiency than interference averaging techniques. Efficient interference avoidance for packet communication requires centralized resource reservation of each data packet individually. This ....

G. J. Pottie, System Design Choices in Personal Communications, IEEE Personal Communications, Oct 1995.

....tra#c. One natural approach is to schedule the transmission of data users signals so as to avoid interference. The main idea is that the increased transmission rate at lower interference more than compensates for the loss in available transmission time. This is the approach advocated in Pottie [10]. The simplest scheme in this direction is intra cell scheduling, where data users packets are transmitted one at a time within each cell. There is no attempt to coordinate these transmissions between base stations. An approach along these lines was examined in Ramakrishna [12] and Holtzman ....

G. J. Pottie (1995). System design choices in personal communications. IEEE Pers. Commun. 2, 50--67.

....cellular systems, the interference fluctuations is handled by so called interference averaging, i.e. frequency hopping or CDMA. This is not possible in DVB T, without a major change of existing hardware. However, that should not be considered as a problem. On the contrary, it was shown by Pottie [8] that interference avoidance, by Dynamic Channel Allocation and power reservation, can perform a factor 2 to 3 better spectrum efficiency than interference averaging techniques. DCA requires centrally controlled base stations. That is especially alluring since we only deal with the downlink, and a ....

G. J. Pottie, System Design Choices in Personal Communications, IEEE Personal Comm., Oct 1995.

....large potential capacity gain of DCA are the difficulties introduced by rapid channel reassignment and intensive receiver measurements required by a high performance DCA or interference avoidance algorithm. OFDM promises to overcome these challenging implementation issues. It was shown by Pottie [8] that interference averaging techniques can perform better than fixed channel assignment techniques, whereas interference avoidance techniques can outperform interference averaging techniques by a factor of 2 3 in spectrum efficiency. For existing second generation systems, the achieved spectrum ....

....whereas interference avoidance techniques can outperform interference averaging techniques by a factor of 2 3 in spectrum efficiency. For existing second generation systems, the achieved spectrum efficiency measured in b s Hz sector (assuming 3 sectors cell) is much lower than that shown in [8], which was obtained under idealized conditions. IS 136 TDMA today provides a spectrum efficiency of about 4 percent (3 x 8 kb 30 kHz x 1 21 reuse) GSM also provides a spectrum efficiency of about 4 percent (8 x 13 kb 200 kHz x 1 12 reuse) IS 95 CDMA provides a spectrum efficiency of 4 percent ....

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G. J. Pottie, "System Design Choices in Personal Communications, " IEEE Pers. Commun., vol. 2, no. 5, Oct. 1995, pp. 50--67.

....value of 20 W. Accurate power control Fig. 2. Downconverted ISM band frequency hopped spectrum in a direct conversion receiver and the large narrowband signals that surround it. by the basestation over this dynamic range is necessary to achieve the potential user capacity of an FH CDMA system [6]. An off chip passive dielectric resonator filter between the PA and antenna suppresses out of band signals at the transmitter output. These out of band signals may be generated within the transmitter, for instance the images around the clock frequency of the discrete time waveforms. Internally, ....

G. J. Pottie, "System design choices in personal communications," in IEEE Personal Commun., vol. 2, pp. 50--67, Oct. 1995.

....more users than the macrocell based system, it poses several problems associated with its cell size. The most notable network issue is the increase of handoff frequency. Several network level solutions have been suggested or implemented for solving the handoff problem in wireless ATM networks [3][4]. Some suggested solutions include Virtual Connection (VC) re establishment[5] VC partial re establishment [6] and VC multicasting methods [7] Contemporary solutions typically use network level approach because they have no way of distinguishing ATM cells at the lower layers (ATM cells do not ....

G.J. Pottie, "System Design Choices in Personal Communication", IEEE Personal Communications, pp. 50-67 Oct. 1995.

....Science Department, University of California, Los Angeles. Gerald Popek is also affiliated with Platinum technology. E mail: geoff fmg.cs.ucla.edu, reiher fmg.cs. ucla.edu, popek platinum.com many research and commercial efforts to rectify this situation by providing wireless communication [1, 2], there are also numerous roadblocks that will either slow deployment for a significant time, or remain fundamentally insurmountable. In contrast to their fixed brethren, wireless systems are expensive, slow, and frequently nonexistent, and the capacity of a wireless system cannot be increased by ....

Gregory J. Pottie. System design choices in personal communications. IEEE Personal Communications Magazine, 2(5):50--67, October 1995.

....it will be assumed that nodes have knowledge of the path losses to all of their one hop neighbors. Indeed, the slow variations of the channel, due to path loss and shadow fading are easily tracked, in contrast to fast fading variations due to multipath which, usually, cannot be estimated easily [9]. Since nodes might have more than one reserved slot in a TDMA frame, they can rely on different parents to receive packets in the different slots. This adds a degree a flexibility to the reservation process, since a single parent node may not be able to relay certain packets in a frame, either ....

G. J. Pottie, "System Design Choices in Personal Communications", IEEE Personal Commun., pp. 50-67, Oct. 95.

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