We use 7 Company Confidential. Nokia Node B restrictions: A maximum of four signatures can be allowed 16 bit field. It aims at providing the required quality: no worse, no better. Too high quality would waste capacity.
Since Fast Fading is uncorrelated between uplink and downlink large freq separation between ul and dl bands in FDD we can not use only a method based on Open Loop Power Control. DL: We do not have Near-Far Problem due to one-to-many scenario: all the signals within one cell originate from one NodeB to all mobiles.
However it is desirable to provide a marginal amount of additional power to UE at the cell edge, as they suffer from increased other-cell-interference. It takes place between the UE and the Node B.
DL inner loop power control control is more complex. The Node Bs transmission power can be changed by 0. If other step sizes are supported or selected, depends on manufacturer or operator. One reason for the UE to request a higher output power is given, when the QoS target has not been met. It requests the Node B to transmit with a higher output power, hoping to increase the quality of the connection due to an increased SIR at the UEs receiver.
But this also increases the interference level for other phones in the cell and neighbouring cells. The operator can decide, whether to set the parameter Limited Power Increase Used. If used, the operator can limit the output power raise within a time period.
Here, the UE is commanded to modify its transmit power every timeslot. This is necessary in very low and high speed environments.
PCA2 changes only with every 5th timeslot, i. This can be seen in the next figure. This adverse effect on the UL performance could be reduced if a PC step size smaller than 1 dB was employed. Algorithm 1 is used when the UE speed is sufficiently low to compensate for the fading of the channel PC step size should be 1 or 2 dB Algorithm 2 was designed for emulating the effect of using a PC step size smaller than 1 dB and can be used to compensate for the slow fading trend of the propagation channel rather than rapid fluctuations.
Control information and user data are time multiplexed. The timeslot length is chips. The exact length of the fields depends on the slot format, which is determined by higher layers. The TFCI is optional, because it is not required for services with fixed data rates. Slot format are also defined for the compressed mode; hereby different slot formats are in used, when compression is archived by a changed spreading factor or a changed puncturing scheme.
The pilot sequence is used for channel estimation as well as for the SIR ratio determination within the inner loop power control. The number of the pilot bits can be 2, 4, 8 and 16 it is adjusted with the spreading factor. A similar adjustment is done for the TPC value; its bit numbers range between 2, 4 and 8. The spreading factor for a DPCH can range between 4 and The spreading factor can be changed every TTI period.
Rate matching is done to the maximum bit rate of the connection. Lower bit rates are possible, including the option of discontinuous transmission. Please note, that audible interference imposes no problem in the downlink, since Common Channels have continuous transmission. Multicode usage: Several physical channels can be allocated in the downlink to one UE. Then, on all downlink DPCHs, the same spreading factor is used.
Also the downlink transmission of the DPCHs takes place synchronous. Multicode usage is not implemented in RAN1. Physical Layer Bit Rates Downlink Spreading factor 64 32 16 8 4 4, with 3 parallel codes Channel symbol rate ksps 7. Their number can be 3, 4, 5, 6, 7 or 8. Variations exist for the compressed mode.
Its spreading factor ranges between 4 and Multicode usage is possible. The transmission itself is organised in 10 ms radio frames, which are divided into 15 Company Confidential timeslots. If DTX is applied in the downlink as it is done with speech then bursts are generated in one second. At the Node B, the problem can be overcome with exquisite filter equipment.
This filter equipment is expensive and heavy. Therefore it cannot be applied in the UE. The minimum TTI period is 10 ms. By reducing the changes to the TTI period, the audible interference is reduced, too. The gain factors may vary for each TFC. The spread complex valued signal is fed to both TX antenna branches, and weighted with antenna specific weight factors w1 and w2.
Mode 1 uses phase adjustmentthe dedicated pilot symbols of two antennas are different orthogonal 2. The same principle is applied for the DPCH. The number of radio frames is set by the higher layers RRC resp. Its value ranges between and 6 dB step size 2 dB.
Planning issues Planning should meet current standards and demands and also comply with future requirements. Uncertainty of future traffic growth and service needs. High bit rate services require knowledge of coverage and capacity enhancements methods. Real constraints Coexistence and co-operation of 2G and 3G for old operators.
Environmental constraints for new operators. Network planning depends not only on the coverage but also on load. Objectives of Radio network planning Capacity: To support the subscriber traffic with sufficiently low blocking and delay. Coverage: To obtain the ability of the network ensure the availability of the service in the entire service area.
Quality: Linking the capacity and the coverage and still provide the required QoS. Costs: To enable an economical network implementation when the service is established and a controlled network expansion during the life cycle of the network. Planning methods Preparation phase Defining coverage and capacity objectives Selection of network planning strategies Initial design and operation parameters Initial dimensioning First and most rapid evaluation of the network elements count and capacity of these elements Offered traffic estimation Joint capacity coverage estimation Detailed planning Detailed coverage capacity estimation Iterative coverage analysis Planning for codes and powers Optimization Setting the parameters Soft handover Power control Verification of the static simulator with the dynamic simulator.
A strategy for dimensioning Plan for adequate load and number of sites. Enable optimized site selection. Avoid adding new sites too soon. Allow better utilization of spectrum. Input data preparation Digital map. Antenna editor. Propagation model editor. Defining service requirements and traffic modelling. Bit rate and bearer service type assigned to each service. For NRT need for average call size retransmission rate.
Traffic forecast. Propagation model tuning. Matching the default propagation models to the measurements. Tuning functions per cell basis.
Link loss calculation. The signal level at each location in the service area is evaluated, it depends on Network configuration sites, cells, antennas. Propagation model. Calculation area. Link loss parameters. Cable and indoor loss. Line-of-sigth settings. Clutter type correction. Topographic corrections.
Optimising dominance. Interference and capacity analysis. Locating best servers in each location in the service area. Target to have clear dominance areas. Iterative traffic planning process Verification of the initial dimensioning. Because of the reuse 1, in the interference calculations also interference from other cells should be taken into account. Analysis of one snapshot. For quickly finding the interference map of the service area. Locate users randomly into network.
Assume power control and evaluate the SIR for all the users. Simple analysis with few iterations. Exhaustive study with all the parameters. Monte-Carlo simulation. Finding average over many snapshots: average, minimum, maximum, std. Averages over mobile locations. Iterations are described by: Number of iterations. Maximum calculation time.
Mobile list generation. General calculation settings. Reporting: Raster plots from the selected area. Network element configuration and parameter setting. Various graphs and trends. Customized operator specific trends. Uplink iteration step Allocate MS transmit powers so that the interference levels and BS sensitivities converge. Min Rx level in BS. Interference situation. Antennae gain cable and other losses.
The power calculation loop is repeated until powers converge. Mobiles exceeding the limit power Attempt inter-frequency handover. Are put into outage. The initial Tx powers are assigned iteratively. The transmit power need for the MS is calculated and compared to the maximum allowed.
Concentration on the power limits per radio link. The transmit power need for supporting the link is calculated and compared to the maximum allowed. This is because the maximum output power of the mobile is lower than for the base station, so the base station can reach longer than the mobile can. Capacity is generally limited by the downlink. This is because better receiver techniques can be used in the base station than in the mobile.
Since most forecasts predict an asymmetric load where the users download data to a larger extent than sending, the downlink will be most important from a capacity point of view. When traffic increases, the level of interference in the system increases. To compensate for this, the mobile has to increase its output power in order to defeat the increased noise, or in already at max power, make the connection closer to the base station.
Due to the increase of traffic, the effective cell area has shrunk. This behavior is known as cell breathing. To reduce cell breathing interference margins are included when dimensioning the network, which has the effect of increasing site density. Coverage Limited Uplink Another way to reduce cell breathing would be to add a frequency, which would mean that the users could be spread over two or more carriers. Since the different carriers are not interfering with each other, the interference level is reduced, and an increase in capacity or coverage is achieved When making the initial design, the aim is to provide a certain capacity, or service level, over an area.
One design strategy could be to design a very low-density network, capable of providing low capacity over a wide area. This would reduce the number of base stations as compared to building for higher capacity.
Since the cost of base stations are a large part of the cost of building a network, minimizing the number of base stations are important. On the other hand, it is important to be able to provide attractive services to the customers. This could be difficult if not enough bandwidth is available. Building less dense means that the maximum distance between the mobile and base station is increased, which is the same as allowing a higher maximum path loss between the two.
A higher path loss between the mobile and the base station can be tolerated if the interference is decreased. If the interference in a cell were reduced by a certain amount of dB, the maximum allowed path loss would increase by the same amount. Coverage Limited Uplink Using a propagation model like for example Okumura-Hata, it is possible to convert a change of the interference level into a changed site density, compared to a reference case.
Table below shows the change in number of sites if the interference margin in the link budget is changed. A negative dB value means that the link budget is worse compared to the reference case, and thus more sites are needed.
Uplink Load Factor Interference degradation margin: describes the amount of increase of interference due to multiple access. It is reserved in the link budget. Coverage Limited Uplink For voice services a typical noise rise would be between dB, which corresponds to a throughput between kbps and kbps. A network is designed for a certain throughput. After some time that throughput is reached, and as a result the noise rise rises over the design value. The choice is then to either increase site density, or add more frequencies.
Adding a frequency has its own set of problems, most notably that soft handover does not work between frequencies. This problem is less of an issue if new frequencies are added to a number of sites over a wider area.
The mobile can then move freely on the frequency it has been assigned, and the probability of making a hard inter-frequency handover is reduced Assume that traffic increases so that the actual noise rise is 4 dB, 1 dB above the design level. The noise figure needs to be improved, for example down to 2 dB, to improve quality and make room for future capacity demands. In other words, the average throughput per cell needs to be reduced.
Building more sites, or adding another frequency can do this. Adding a second frequency would half the throughput for each cell and carrier. For a 4 dB noise rise the throughput is kbps according to the graph. The cost of building these sites can then be said to be the value of having one extra frequency. Adding a second and a third frequency follows the same pattern, with a slight difference. The relative decrease in noise rise will be lower.
When a third frequency is added the traffic is spread over three carriers, and reduced with a third for each frequency. Coverage Limited Uplink It is also possible to do the other way around, that is, build sites less dense to start with.
This saves money in the roll out phase, but could cause problems if high capacity is needed in the future. Using figures from the example above, assume a design for a maximum throughput of kbps for one carrier, which corresponds to a noise rise of 3 dB. The saving is 2. This is the same as each site covers approximately 1. Uplink Coverage of Different Bit Rates 3. Recommended Values 0.
Number of users per cell Activity Factor of user j at physical layer Signal energy per bit divided by noise spectral density that is required to meet a predifined BLER. Downlink Load Factor Compared to the uplink load equation, the most important new parameter is j , which represent the orthogonality factor in the downlink. WCDMA employs orthogonal codes in DL to separate users, and without multipath propagation the orthogonality remains when the base station signal is received by the mobile.
The DL load factor exhibits very similar behavior to the UL load factor, in the sense that when approaching unity, the system reaches its pole capacity and the noise rise over thermal noise goes to infinity For downlink dimensioning, its important to estimate the total amount of base station transmission power required.
This is based on average transmission power for user. Capacity Limited Downlink As the demand for downlink capacity increases, there are several different ways of increasing capacity. The most common ways are adding more frequencies and power amplifiers, and introducing transmit diversity Upgrading capacity in the ways just mentioned is of course dependant on the base station equipment being able to handle it.
It is reasonable to assume that as the capacity demand increases, the equipment vendors will produce equipment that can handle it Assume an initial base station configuration of one 20W power amplifier per sector, one carrier per sector and three sectors per site. This is called the baseline configuration, and has a baseline capacity The first step to upgrade the capacity is to add a second frequency.
The second step could be to add a second 20W power amplifier restoring the power per frequency to 20W and introduce transmit diversity STTD, Closed loop mode 1, Closed loop mode 2. Rating edition incropera Fundamentals of Heat and Mass Transfer Incropera 7th edition solutions manual. Introduction for Chemical Engineering R. We have solutions manuals for solutions manual Introduction to Engineering and Heat Transfer Nellis Klein solutions manual. Get instant access to our step-by-step Introduction To Heat Transfer solutions manual.
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By Introduction to Heat Transfer, 6th Edition. Table Of Contents. Two threshold uplink rate control to enable uplink scheduling more. Method for controlling terminal fault corrections in cellular system more. Wireless Device Locations Services more.
A flexible and simple TDD air interface capable of allocating capacity asymmetrically between the uplink and downlink is considered. Such an air interface is well suited for providing asymmetric high bit rate services.
The main emphasis has been in describing the physical channel structures. As the FMA2 has been designed to support variable and high data As the FMA2 has been designed to support variable and high data rate transmission, also the service multiplexing and the random access issues are discussed. An ideal TDD system offers high capacity, dynamic asymmetry between uplink and downlink and no coordination requirements between operators and base stations.
Since both uplink and downlink share the same frequency in TDD, those two transmission directions can interfere with each other. Spread Technology to Africa Cat. Spread Spectrum. Code Division Multiple Access. Load Balancing and Performance Optimization. Release 11 and Outlook towards Release 12 more.
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