How far to re-use Scrambling Code?

For 3G live Network. Please check

1. According to your scanner tool result.Same SC within same area are prohibit.
2. Check in neightbor list.No same SC in each NB list.

Did you agree with me?

UE Sensitivity VS HSDPA Throughput

Today,I perform 3G in building walk test for HSDPA.I found that UE sensitivity is an another major factor of HSDPA speed. Less UE sensitivity will make low T/P.

I think that CQI effected by UE sensitivity.

Low sensitivity --> Low RSCP --> Low Ec/Io --> Low CQI --> And low HSDPA T/P
More sensitivity --> High RSCP --> High Ec/Io --> High CQI --> And absolutely High HSDPA T/P

HSDPA Miss Understood

On last workday I found miss understood with my colleague,he say he want to make HSDPA network with guarantee bit-rate all of certain area, So poor man I said to him "Did you known HSDPA throughput are Best Effort"

You can't guarantee HSDPA bit-rate,Actually its depend on CQI (Channel Quality Indicator) but finally its depend on number of user among that cell.Throughput are very on CQI and number of user time by time.

Almost all of telecommunication engineer who was work with 2G system alway confuse with this topic.

:Mark my word pal, "HSDPA T/P are Best Effort"

RRM Admission Control

Admission control decides whether or not an incoming call can be accepted. A new radio connection is admitted by the CRNC which accounts for the available resources at the corresponding Node B. The allocation of resources includes the allocation of the corresponding downlink spreading and channelization code pair. The objective of admission control is to maintain call quality in each cell by limiting admission of radio bearers. If radio bearers were granted without limit, the interference level in the cell would increase, leading to degradation of the call quality. In addition to the admission control function in the RNC, the Node B performs admission control to protect the Node B against too high transmission power requirements. The Node B estimates the transmission power requirement of a new radio link and verifies whether the total transmission power is below the maximum allowable transmission power.

Feature comparison between R99 and HSDPA

Above is feature comparison of HSDPA and R99.For my opinion the big change are Modulation Scheme, TTI and Soft Handover Type.

Let talk about Handover, for HSDPA only one active set can be clamp in one time. Modulation scheme very due to air condition time by time (Ec/Io) and Transmission Block reduced to 2 ms.

What is UMTS RRM Function ?

The function for managing radio interface resources of the UMTS Terrestrial Radio Access Network (UTRAN) are called Radio Resource Management (RRM) function. The RRM functions aim to ensure the optimum coverage and high call quality as well as to maximise the system performance through efficient use of radio resource.

You can down load All 3GPP DOC. from 3GPP FTP Link

Multi carriers dedicated for HSDPA and R99

The advantage of this carrier strategy is the performance improvement of both HSDPA and R99 calls. Since the separated carriers are prepared for each technology, the possible interference between R99 and HSDPA would be minimized. In this configuration, the code allocation problem shown in single carrier strategy can be also avoided. The disadvantage of this configuration is an impact on the investment and running cost since this configuration will require high power amplifier for multi carrier operation and other necessary resources such as Iub and base-band resources which is necessary to be prepared for each cell (e.g. common channels). In some case, the licensing scheme contracted between operator and vendor may be also related. If cell license is applied in the contracted license scheme, the increase of the number of cells will affect on the amount of license fee to be paid.Another concern of this cell configuration strategy is the mobility of HSDPA call. The following figure illustrates the case that the area where single carrier strategy is applied is adjacent to the area where multi carrier is applied. Fig. below HSDPA mobility problem In this case, when HSDPA user is going to move from single carrier area to multi carrier area, HSDPA user prefers to be handed over to the HSDPA cell for HSDPA service continuity.

In this case, when HSDPA user is going to move from single carrier area to multi carrier area, HSDPA user prefers to be handed over to the HSDPA cell for HSDPA service continuity.

However it depends on the supported functionality of the equipment vendor and also depends on the specification of the terminal, even if vendor would like to choose this mobility scenario. In addition, there would be the interruption time during inter frequency handover process in this scenario and such interruption time may worse the end-user experience. Thus the parameters tuning shall be done to minimize the interruption time as much as possible.

Single carrier shared between HSDPA and R99

The advantage of sharing single carrier between HSDPA and R99 is the resource efficiency.Since HSDPA uses the transmission power of Node-B which is remained after the power assignment to R99 calls. Therefore, if the traffic of R99 call is low, the remaining power available for HSDPA will be high and high HSDPA performance will be expected. Another advantage is that sharing the single carrier could save the operator’s investment and running cost of Node-B. The disadvantage of this configuration is an impact on the performance of end-user experience. If the traffic volume of R99 call becomes high, the remaining power available for HSDPA will be reduced and as a result HSDPA performance received at end-user will also become low. In addition, HSDPA can become interferer to R99 call since HSDPA can use all the remaining transmission power. Such a high power transmission would increase the interference on R99 call and it would lead to the shrink of R99 service area.

Another disadvantage of single carrier configuration is the restriction on code allocation. In single carrier configuration, the channelization codes are also shared between HSDPA users and R99 users. If dynamic code allocation function is not implemented, the fixed channelization codes for HSDPA have to be reserved in advance and R99 users have to use the remaining channlization codes which belong to the same code tree. The following figure is the example that 15 channelization codes of SF16 are reserved for HS-DSCH and that FACH and PCH are mapped on to the different S-CCPCH. In this case, the channelization codes for DCH, CCH, HS-SCCH has to be allocated from the rest of code tree. For Common Channels, P-CPICH, P-CCPCH, AICH, and PICH use one channlization code of SF256 respectively and FACH uses one channlization code of SF64 and PCH uses one channelization code of SF128. Thus DCH and HS-SCCH can use the rest of the code tree.

This example above shows that 3 channelization codes of SF128 are allocated for HS-SCCH. But in this code allocation, it is found that no channelization code is left for DCH if 15 channelization codes of SF16 are reserved for HS-DSCH and if FACH and PCH are mapped on to the different S-CCPCH and if 3 channelization codes of SF128 are allocated for HS-SCCH. In addition, from above, it is also found that up to 3 HS-SCCH can be allocated if 15 channelization codes of SF16 are reserved for HS-DSCH and if FACH and PCH are mapped on to the different S-CCPCH.

HSDPA Cell Configuration

In order to start HSDPA service in the network, one of the biggest issues for operators is which kind of cell configuration scenario shall be selected since the number of cells deployed in network will affect the number of Node-B hardware and have a direct impact on the investment and its running cost.

From operator’s viewpoint, the network resource efficiency must be maximized as much as possible, on the other hand from end-user viewpoints, much higher end-user throughput is needed but in such case the network efficiency will be worse if the generated traffic as a network is quite low. Therefore the trade-off relations between network efficiency and end-user experience can not be avoided and operator must choose their cell deployment strategy depending on the environment to deploy HSDPA and traffic demand there with considering the balance of end-user experience and network efficiency.

The following figure shows the possible cell configuration of HSDPA when operator starts to deploy HSDPA. At initial stage, operator has to choose the one from the two scenarios, that is, whether HSDPA shall share the single carrier with R99 (Single Carrier Strategy)or HSDPA shall use the dedicated carrier separated from R99 carrier (Multi Carrier Strategy).

HSDPA Planning

As Mobile broadband has been accelerating, high speed packet access technology will have a great impact on the business of mobile operators for not only private users but also enterprise users. In order to grab the business opportunity, operators have to study how they will introduce this new technology in their network and attract their subscribers with new application service and have to find the cost-effective way to establish such high speed packet access network but have to satisfy the enough end-user experience at the same time.

HSDPA deployment for indoor will be also the key issue for operators because the high speed packet service will be highly demanded in indoor environment, thus indoor deployment of HSDPA will be also described in this document. Other topics, which are related to dimensioning of resource consumption such as channel element and code resources

Radio Planning of the UMTS networks

The first step of radio planning of the future network is the rough estimation of the number of required sites in particular areas. This dimensioning process starts with the link budget calculation. The link budget has to be analyzed for each area type and phase of the planned network as the used parameters e.g. penetration loss or required shadowing margin change with the area type and some of the parameters, e.g. target bearer with the implementation phase.

The cell coverage is calculated with an appropriate propagation model from the maximum allowed pathloss that is determined in the link budget calculation. . The maximum allowable pathloss consists of two parts – the system pathloss and the pathloss due to coverage requirements.

The system pathloss is basically the difference between the minimum allowable receive level at the UE respectively at the Node B receive, and the transmitting power (EIRP) at the corresponding nodes. The EIRP comprises of the antenna gains and feeder/combiner losses.
The minimum receive level takes into account the thermal noise, the carrier bandwidth, the bearer data rate noise figure of the receivers, the initial assumptions for the required Eb/No values (derived from link level simulations), interference situation due to the presence of the users in the system, as well as diversity gains and correction margins (caused by the considered environment).

The value of the additional interference margin, covering the noise rise in the system that appears in the link budget calculation, comes from the previous considerations regarding the traffic/load situation in the network.The coverage requirements are considered by taking into account the shadowing margin and penetration loss. The required location probability (cell area or edge) and the assumed standard deviation of the slow fading define the shadowing margin. The penetration margin is defined per clutter type of the analyzed area.

The propagation model depends on the clutter type and the chosen cell type to be planed. Typically three major cell types are assumed – macro cells, micro cells and pico cells.Results of the Link Budget calculation are used in the next steps of the planning process, which are the traffic dimensioning and the detailed deployment specific radio planning with the radio planning tool.

Common Input Parameter

The first step of the link budget calculation is to decide for which clutters, user types, cell and bearer types calculation should be done in a certain area and certain phase of the network. Setting of these “common input” parameters will determine further link budget parameters (or their ranges) that are used in the calculation of Maximum Allowable Pathloss.

Bearers
3G technology provides a variety of bearers offering different data rates and quality of service classes to the users. Within the operating network there will be always a mix of services present at each point in time. All these bearers can be offered in the whole of the cell area. However the probability of the bearer availability decreases with the distance from the Node B. Together with the marketing department, the planner has to decide for which bearers, link (i.e. uplink or downlink) and with which probability the coverage should be ensured in a particular area. Usually, the higher the data rate of the bearer the smaller the cell range. Also the cell ranges for circuit switched services are usually smaller than the ones for packet switched services. Uplink cell ranges (except for Voice bearer) are usually smaller than the downlink cell ranges. The limiting bearer and link should be therefore chosen as a target for each planned area and phase.For a detailed description of the possible bearers, please also refer to the section describing the traffic model.

HSDPA bearers

HSDPA bearersIn UMR5.0 HSDPA applies for PS Interactive/Background calls, of the Release 6 UEs,that are held on the shared HSDPA channel. 12 UE categories are standardized from which 8 are supported in UMR5.0: 1-6, 11 and 12. The qualities that differentiate the UE categories from each other are, for example, the supported modulations (QPSK or QPSK/16QAM), the maximum number of HSDSCH codes received (5, 10 or 15) and the maximum data rate. Depending on the current situation in the cell (interference level, available power, UE categories, traffic demand …) the scheduler decides the number of HS-PDSCH codes sent to the particular user, as well as about the modulation and coding rate used and the number of transmissions that are required. Unlike in Rel. 99, there are a lot of different coding rates possible for bearers in HSDPA: from 0.143 up to 0.887 resulting in data rates of 69kbps up to 852kbps per code. Consideration of all the coding rates would result in extremely complex link and system level simulations, as well as related Link Budget and traffic calculation.For simplicity, seven modulation and coding schemas (MCS) were selected for HSDPA coverage and capacity considerations:

Clutter types

Many Clutters (morphological area types) can be defined. In real network planning thenumber of used clutter types can be 15 and more. Such detailed data/maps appreciated in the tool planning, can however be a big problem during the early dimensioning phase. That is why during the first phases of the planning number of considered clutters is usually reduced to: Dense Urban, Urban, Suburban, Rural and Road. Choice of the clutter has an impact on the used propagation model but also other parameters like penetration loss and shadowing margin. A short description of the used clutter types is given below.UrbanAreas with high building density as found mostly in urban environments consisting of large buildings, offices, shops etc. and adjacent buildings clearly distanced from each other. The typical urban scenario should have mean amount of streets with no distinct street orientation pattern and the major streets are visible on satellite maps. The buildings appear distinct from each other. Some small vegetation can be included. The average height of the buildings is below 40m.

Dense Urban

Areas within the urban environment with a highly concentrated building density. Single features do not clearly appear distinct from each other e.g. on a satellite map. Heights of the buildings can be well above 40m.

Suburban

Areas of housing that include some vegetation, mostly found bordering the urban areas, spreading outwards from the city center. Average height is below 15m.

Road - Quasi Open

This clutter type corresponds to regions (rural areas) outside city areas without large development; villages, smaller vegetation, roads.

Rural - Open

The Rural clutter corresponds to areas without buildings like water, trees etc.

Correct estimation of the clutter area size is very important during the first dimensioning phase. A wrong estimation can lead to big discrepancies in required number of sites calculation.

Cell Types

In general we can distinguish macro, micro and pico sites. The macro cell is characterized by an antenna height of more than 3m above the average building height in the surrounding area. The micro cell is deployed e.g. in street canyons and the antenna height is about 3m to 6m above the ground and therefore significantly lower than the roof top height. The pico cell is deployed in the building and provides mainly indoor coverage. Macro sites can be divided into omnidirectional sites and sectored sites i.e. two-sector or three-sector sites. The latter type can be further split with accordance to the layout e.g. cloverleaf or rhomboidal. Link budget calculation presented further is valid for these kinds of site configurations.