S. Sheng, A. Chandrasekaran, and R.W. Broderson, "A Portable Multimedia Terminal for Personal Communication," IEEE Comm., pp. 64-75, Dec. 1992.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....are listening. Hence, this public storage scales well with an increase in the number of users. Fig. 1. Wireless information servers. IMIELINSKI et al. DATA ON AIR: ORGANIZATION AND ACCESS 355 1. 1 Motivation The lifetime of a battery is expected to increase only 20 over the next 10 years [11]. A typical AA cell is rated to give 800 mA hr at 1.2 V (0.96 W hr) The constraint of limited available power is expected to drive all solutions to mobile computing on palmtops. Assume that the power source of a palmtop with a CD ROM and a display, to be 10 AA cells. The constant power ....

S. Sheng, A. Chandrasekaran, and R.W. Broderson, "A Portable Multimedia Terminal for Personal Communication," IEEE Comm., pp. 64-75, Dec. 1992.

....environments can be evaluated on the following parameters. ffl Number of uplink requests: Minimizing the number of uplink queries is a desirable goal as hosts in a mobile environment have limited battery power. The lifetime of a battery is expected to increase only 20 over the next 10 years [SCB92] . Transmitting data requires a lot more power than receiving data, thus uplink queries are more expensive than down link broadcasts. ffl Throughput: Wireless bandwidth is a scarce resource. Compared to the bandwidth available on wired networks, wireless bandwidth is limited. Given this ....

S. Sheng, A. Chandrasekaran, and R.W. Broderson. A portable multimedia terminal for personal communications. IEEE Communications Magazine, pages 64--75, December 1992.

....of a mobile host to operate while on the move requires a stand alone source of power such as batteries. Unfortunately, the progress of battery technology is very slow compared to the dramatic improvement of technology of CPU and memory capacity. This, gets clear from the results of a study by [Sheng92] estimating that battery lifetime will increase only 20 over the next 10 years. The restrict battery resources on mobile computers force designers to give a great attention to this factor during the software and hardware design of a mobile unit. This lead to an e ort so that the equipment of a ....

Samuel Sheng, Anath Chandrasekaran, and R. W. Broderson, \A portable multimedia terminal for personal communications", IEEE Communications Magazine, December 1992, pp. 64-75.

....in one of the minor cycles. By receiving the cluster of data frames together, the mobile computer can answer the query without continue to monitor the rest of broadcast cycle. 3. POWER CONSERVING INDEXING It is expected that the lifetime of batteries will increase only 20 over the next 10 years [14]. Thus, power conservation is a key issue for battery powered mobile computers. Wireless data broadcast is efficient for disseminating data of common interest to a massive number of mobile users. Furthermore, indexing techniques can be employed to predict the arrival time of a requested data item ....

S. Sheng, A. Chandrasekaran, and R.W. Broderson. (1992). A portable multimedia terminal for personal communications. IEEE Communications Magazine, pages 64-75.

....for each of the subsystems, and discuss some of the problems associated with them. Section 5 presents ideas for the Power Broker. 2 The Problem with Batteries Figure 1 shows the approximate time it takes for the some of the major subsystems of a laptop to double in performance or capacity [2, 20]. In general, an unmanaged performance or capacity increase also indicates some increase in power consumption. Based on current research, the growth rate of battery power output through the year 2000 is expected to be no more than 20 [20] Advancements in power storage technology are slow in ....

....of a laptop to double in performance or capacity [2, 20] In general, an unmanaged performance or capacity increase also indicates some increase in power consumption. Based on current research, the growth rate of battery power output through the year 2000 is expected to be no more than 20 [20]. Advancements in power storage technology are slow in comparison to the other subsystems of a mobile computer. Presently there is a shift from Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMH) batteries to Lithium Ion (Li ion) which has a better gravimetric energy density (i.e. energy per ....

S. Sheng, A. Chandrasekaran and R. W. Broderson, A Portable Multimedia Terminal For Personal Communications, IEEE Communications Magazine, pp. 64-75, December 1992.

....for the some of the major subsystems of a laptop to double in performance. In general, an unmanaged increase in performance also indicates some increase in power consumption. Based on current research, the growth rate of battery power output through the year 2000 is expected to be no more than 20 [15]. It is quite clear that unless there is a major advance in battery technology or power management, the mobility of mobile computers is going to be severely restricted by short battery life. Subsystem Years to double performance Measure used Processor 1 year MIPS Memory 2 years Capacity Disk 3 ....

S. Sheng, A. Chandrasekaran and R. W. Broderson, A Portable Multimedia Terminal For Personal Communications, IEEE Communications Magazine, pp. 64-75, December 1992.

....connection to the network. The notion of a cell and the associated wireless communication with a broadcast capability, is absent from portable computing. 3 Projections of progress in battery technologies show that only a 20 improvement in battery capacity will occur over the next ten years [15]. and or security of data is a major concern, the network of fixed hosts offer a more secure and reliable environment than the mobile hosts. The above discussion underlines the need to explicitly account for the effects of changing location of mobile hosts and incorporate their specific physical ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson. A portable multimedia terminal for personal communications. IEEE Communications Magazine, December 1992.

.... 2x 4x 6x 8x 10x 12x 14x 16x Processor (MIPS) Memory (Capacity) 1x Hard Disk (Capacity) Figure 1: Approximate performance capacity growth of major laptop components Figure 1 shows the approximate time it takes for the some of the major subsystems of a laptop to double in performance or capacity [2, 19]. In general, an unmanaged performance or capacity increase also indicates some increase in power consumption. Based on current research, the growth rate of battery power output through the year 2000 is expected to be no more than 20 [19] Advancements in power storage technology are slow in ....

....of a laptop to double in performance or capacity [2, 19] In general, an unmanaged performance or capacity increase also indicates some increase in power consumption. Based on current research, the growth rate of battery power output through the year 2000 is expected to be no more than 20 [19]. Advancements in power storage technology are slow in comparison to the other subsystems of a mobile computer. At present there is a shift from Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMH) batteries to Lithium Ion (Li ion) which has a significantly better gravimetric energy density ....

S. Sheng, A. Chandrasekaran and R. W. Broderson, A Portable Multimedia Terminal For Personal Communications, IEEE Communications Magazine, pp. 64-75, December 1992.

....cater individually to each request. Periodic data broadcasting is the main topic of this paper. MOTIVATION Power conservation is a key issue for small palmtop units which typically run on small AA batteries [2] The lifetime of a battery is expected to increase only 20 over the next 10 years [7]. A typical AA cell is rated to give 800 mA Hr at 1.2 V ( 96 W Hr) The constraint of limited available energy is expected to drive all solutions to mobile computing on palmtops. Assuming that the power source of the palmtop to be 10 AA cells with a CD ROM and a display, the constant power ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

....system which has power saving features built in and provides perhaps the first example of the energy efficient systems software. Perhaps the most surprising limitation, at least to computer scientists, is that the lifetime of a battery is expected to increase only 20 over the next 10 years [18]. This is an extremely slow rate especially comparing to the fast progress in the areas of memory capacity and CPU speed. Hence, there seems to be a long term need for energy efficient solutions in all aspects of the systems software including, as we will show later in the paper, data management. ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

....true. Stock reaching a particular level, traffic congestion on a particular street, a plane departure delayed can all be examples of events which a mobile user may be alerted about. Motivation for Energy savings : The lifetime of a battery is expected to increase only 20 over the next 10 years [21]. A typical AA cell is rated to give 800 mA Hr at 1.2 V (0.96 W Hr) The constraint of limited available energy is expected to drive all solutions to mobile computing on palmtops. Assuming that the power source of the palmtop to be 10 AA cells with a CD ROM and a display, the constant power ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

....mode In the next section, we discuss another resource limitation which may have a profound influence on the way data access algorithms are designed on the mobile platform. 4. 2 Energy Efficient Data Management The lifetime of a battery is expected to increase only 20 over the next 10 years [26]. This is a extremely slow progress comparing to the dramatic improvements in the CPU speed and memory capacity. Typically 1 AA cell is rated to give 800mA Hr at 1.2 V ( 96 W hr) A Ni Cd battery pack is rated at to give 2.4 A Hr at 10.8V (25.92 W Hr) The constraint of limited available energy ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

....desired data, and (3) the number of index channels used to transmit the index. Tuning time is a particularly important measure since PCS units consume valuable energy receiving wireless packets for that period of time, while at other times they consume minimal power by lapsing into the doze mode [SCB92]. Since the amount of power consumed while receiving packets is about 5000 times the power consumed while in the doze mode [SCB92] it is important to try and minimize the tuning time of the power starved PCS. From now, we will refer to the time spent downloading index information as tuning time, ....

.... PCS units consume valuable energy receiving wireless packets for that period of time, while at other times they consume minimal power by lapsing into the doze mode [SCB92] Since the amount of power consumed while receiving packets is about 5000 times the power consumed while in the doze mode [SCB92], it is important to try and minimize the tuning time of the power starved PCS. From now, we will refer to the time spent downloading index information as tuning time, since the tuning time to download the data file (once an index pointer is obtained) is constant and independent of the indexing ....

S. Sheng, A. Chandrakasan, and R.W. Broderson. A portable multimedia terminal for personal communications. In IEEE Communications Magazine, pages 64 -- 75, 1992.

....file systems were the first to deal with the disconnection on the file system level. In databases disconnection is handled typically in the context of long term transactions. ffl Power Considerations Energy is an important constraint due to the battery life limitations. As pointed out by [6], the battery life is not expected to increase more than 20 percent in the next 10 years. Hardware manufacturers are providing hardware solutions such as spinning down the disk and switching off the screen. It is necessary now to provide energy efficient software solutions. Some initial work in ....

Samuel Sheng, A.Chandrasekaran and R.Broderson, "A Portable Multimedia Terminal for Personal Communications", IEEE Communications Magazine, pp 64--75, December, 1992

.... and notebook computers, to access a large number of databases via wireless networks, has recently been identified as an area with an emerging market [5] A significant amount of research effort has been elaborated upon exploring several aspects of mobile computing, including energy saving [6] [8], cache management [1] query processing [4] and data allocation. As reported in [3] the potential market for mobile computing applications is estimated to be in billions of dollars annually. Such applications as using palmtops to access airline schedules, stock activities, traffic conditions and ....

S. Sheng, A. Chandrasekaran, and R. W. Broderson. A portable multimedia terminal for personal communications. IEEE Communications Magazine, pages 64--75, 1992. Data record R1 R2 R3 R4 R5 R6 R7 R8 R9 P r(R i ) .4 .4 .05 .05 .02 .02 .02 .02 .02

.... ondemand mode it makes sense to batch requests for the same data and send the data once rather than cater individually to each request. Periodic data broadcasting is the topic of this paper. 1. 1 Motivation The lifetime of a battery is expected to increase only 20 over the next 10 years [She92]. A typical AA cell is rated to give 800 mA Hr at 1.2 V (0.96 W Hr) The constraint of limited available energy is expected to drive all solutions to mobile computing on palmtops. There is a growing pressure on hardware vendors to come up with the energy efficient processors and memories. The ....

Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

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Samuel Sheng, Ananth Chandrasekaran, and R. W. Broderson, "A portable multimedia terminal for personal communications," IEEE Communications Magazine, December 1992, pp. 64--75.

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