For very low power applications, it can be switched off at certain times of the day using the power switch built into some dataloggers or using an optional PSW12 solid state switch. The utility provides setup and diagnostic features and can be used to view signal strength.
Submit an enquiry Submit an enquiry. Some accessories, replacement parts, or services may still be available. It is functionally equivalent but in a smaller package. Read More. Benefits and Features Ready-to-go kits for easy communication over GSM networks Quad-band Edge compatible transceiver supports transparent and non-transparent modes so is compatible with most GSM networks worldwide Can be used to collect data at speeds comparable with land line modems Supports incoming and outgoing calls, e.
Downloads Mobile Data Assistant v. Download Now. In our simulation we have used Partial Sharing scheme as suggested by Baynat and Eisenmann and Lindemann and Thumber since it guarantees an amount of BW to be shared between all the active data users. We have divided this Partial Sharing scheme into 3 parts because partial sharing is a combination two schemes, permanent allocation which provides exclusive BW to data user and dynamic resource allocation the capacity available for the voice is shared between data users and voice users.
In order to guarantee QoS requirements we need to optimize resource allocation, which is the combination of scheduling mechanism and efficient resource utilization. To achieve this goal we first need to define the QoS level required for example throughput, acceptable blocking probability , then estimate the number ofPDCH channels required to provide the defined QoS level for data traffic.
Synchrophasors Transmitted Over GPRS
We can define the QoS level by investigating the dependency of IP throughput by the user in the cell. We have reconfigured the parameters and modified some scripts on the Network Simulator NS-2 Jain, so that the BS is interfaced with wired nodes using hierarchical routing to simulate the GPRS network. The MAC protocol instances are operating with random access sub channels per 52frame. LLC windows size is fixed at 16 frames. The e-mail model describes the traffic arising with the transfer of message downloaded from a mail server by an electronic mail user. The only parameter is the amount of data per e-mail.
The value of byte as the e-mail size is chosen, since it is assumed that no emails with large attachments will be downloaded on mobile devices. Distribution of e-mail size is log 2-normal. A constant base quota of byte is added to this size. WWW sessions consist of requests for a number of pages geometric distribution with mean 5. Intervals between pages are distributed with negative exponential distribution mean 12 sec.
These pages consist of a number of objects with a dedicated object s1ze. The number of objects per page 2. The inactive period between two sessions is set to 15 sec. The maximum IP throughput in DL is taken as 24 kbit sec -1 and average IP throughput per user is IP throughput in downlink measured during period of transmission. This measure is evaluated statistically by counting the amount of IP bytes transmitted in each TDMA frame period for each user, if a packet train is running.
The throughput is averaged over active periods only. From our defmition a small value of C v means increased number of voice blocked calls and small value of C d will affect the QoS requirement for PDCHs. Using the above parameters we can estimate the number of PDCH required and can be found by following equation.
Using graph we first locate the operating point Q defined by the QoS target and total offered traffic. Q is a reference point used to judge whether the corresponding curve falls within the expected region or not.
The Q point in our simulation is the intersection between If E-mail curve and Web curve are considered separately their curves appear to be very close Fig. Usually the GRPS users can be dynamically allocated available BW reserved for voice services depending upon the desired level of blocking probability. Let us consider the total capacity of the cell C. Erlang table is used to determine the air interface in GSM.
Synchrophasors Transmitted Over GPRS
Considering calls per hour with average time duration of call is 90 sec, then by using Erlang table the number ofErlang can be obtained as following. Let P j be a steady state probability that j users are in active transfer and the average overall throughput X T of the resource is obtained as. Where is equal to the number of new arrival users. Using Erlang table means 22 TCH chmels are needed. Fifteen or more chmels may be reserved for GSM users at any one time to prevent a level of call blocking during rush hours.
Implementing CS-2 coding scheme, 90 kbits sec -1 can be achieved without increasing the number of channels. From Fig. The IF throughput depends on the characteristic nature of the traffic generator, for example low data volume such as Email have shorter TBF duration while high data volume such as Web have longer TBF duration thus occupies radio resource for long period of time causing throughput performance degradation. Therefore to achieve optimum network configuration, Q point must be define and traffic load should be carefully examined, then parameters like number of fixed PDCH.
Combination of static and dynamic allocation: Ithas been observed that dynamic allocation does not provide efficient utilization of chmels due to implementation complexity and signalling effects likewise static allocation result into inefficient resource utilizations because one party may be overloaded while the other is rmder utilizing the resources reserved for it. Thus a combination of both schemes may provide an optimum solution. For operator to guarantee network accessibility, must choose proper fixed number of GPRS and dynamically allocate the rest efficiently.
In this study we investigate methods that would enable proper estimation of necessary resources, namely number of PDCHs cbonnels. The procedures on how to estimate necessary resources are also given, we have used static, dynamic and combination of both static and dynamic scheme to support the proposed methods.
Through our simulation results, we have demonstrated that in order to achieve resources optimization then proper traffic scheduling methods should be implemented, therefore in this paper after careful investigation we have proposed criterion that can be applied for reserving a fixed number ofPDCH for GPRS services and dynamically allocate the rest of the channels for voice and GPRS services.
Besides throughputs and blocking probability other factors need to be considered are composition of offered traffic, loss of packets, latency, jitter and the influence of multi-slot capability on network traffic. Baynat, B.