CHANNEL ELEMENT (CE) – HUAWEI SYSTEM 

A channel element (CE) is defined as the baseband resources required in the Node B. On the RNC side, it is referred to as the NodeB credit. On the NodeB side, it is referred to as the Channel Element (CE).

The consumed NodeB resource of one equivalent 12.2 kbit/s AMR voice service, including 3.4 kbit/s signaling on the Dedicated Control Channel (DCCH), is defined as one CE. If there is only 3.4 kbit/s signaling on the DCCH, one CE is consumed. There are two kinds of CE. One is uplink CE supporting uplink services, and the other is downlink CE supporting downlink services. Therefore, one 12.2 kbit/s AMR voice service consumes one uplink CE and one downlink CE.

Figure 4-2 Baseband CE Resources

Maximum CE resources in one NodeB depend on the baseband card capabilities and on the CE licenses (uplink and downlink). The CE licenses in one NodeB can be shared between carriers and sectors

l Common Channels have dedicated CE resources (No impact on CE license) l HSDPA (UL, DL) have dedicated CE resources (No impact on CE license) l R99 DCH (UL, DL) and HSUPA take resources from CE license l R99 and HSUPA channels share the same pool of CE resources

CE Sharing

A cell must be set up in an uplink resource group (ULGROUPN) and a downlink resource group (DLGROUPN) respectively. In the uplink, CE resources can be shared in one resource group dynamically. In the downlink, CE resources can be shared in one board. A cell can be set up in only one board of the downlink resource group.

CE Consumption and Admission.

CEs consumption is determined by SF. RNC performs admission based on the NodeB capability, license CEs and the service required CEs.

Dynamic CE Management

Overview

This section involves the feature "WRFD-010638 Dynamic CE Resource Management."

CE resources are hard resources used for channel modulation and demodulation. Generally, if the service rate is higher, more CE resources are required. To ensure the QoS, CE resources need to be allocated on the basis of the maximum bit rate of users. In this case, if fixed CE resources are allocated to users, the resources are wasted when the rate of the service source is low. The rate of the services that are carried on the HSUPA channel and configured in scheduling mode can be controlled by the scheduling module. Thus, dynamic CE management is used. That is, CE resources to be allocated to users are adjusted dynamically according to the conditions of CE resources and the change of user requirements to improve the utilization of CE resources.

The following shows an example of comparison between CE consumption with or without dynamic CE management.

Comparison between CE consumption with or without dynamic CEmanagement

 

The rules for dynamic CE resource allocation are as follows:

When the rate of the service source decreases, the redundant CE resources are called back.

When there is a need to increase the service rate, CE resources are reserved. When there are insufficient available CE resources, CE resources are allocated

to users in the serving RLS preferentially because the QoS of users depends on the resource allocation of the serving cell.

When the available CE resources are insufficient to meet the requirements of all the users in the serving RLS, user priorities need to be considered to provide differentiated services.

In addition, the dynamic CE management module needs to process messages from external functional modules, such as the resource allocation request during the establishment of a new connection and the channel reassignment request. In such a case, the QoS requirement of users and user priorities must be considered.

Dynamic CE management has no function switch parameter.

Dynamic CE resource management increases the CE efficiency in the network and improves the system capacity.

HSUPA users with rate range from 32 kbps to 320 kbps will consume more CEs when dynamic CE resource management is enabled than when HSUPA DCCC is enabled. If the rates of a lot of HSUPA users are in that rate range, enabling the feature will result that the CE resource is more likely to be congested and thus affect the access success ratio.

Procedure

Procedure of dynamic CE management

The main functions of the dynamic CE management module are shown in Figure 4-4. The procedure of dynamic CE management is as follows:

Step 1 Calling back CE resources

Based on the actual data rate of users, the CE management module calls back the idle CE resources to improve the utilization of resources and updates the information about available system resources.

Step 2 Processing external related messages

Based on the requirement of external signaling messages, the CE management module allocates appropriate CE resources to users and updates the information about available system resources.

Step 3 Increasing CE resources dynamically

Based on the estimation of the requirement for CE resources, the CE management module increases CE resources for users with the requirement for increasing CE resources. If the available CE resources are insufficient after the processing in the first two steps, the CE management module provides differentiated services and adjusts CE resources among users dynamically based on user priorities.

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Steps 1 to 3 can be triggered periodically, and the periods can be different. Step 2 is triggered by events. If several processing tasks are triggered at a time, the CE management module performs the processing by following the procedure shown in Figure above.

CE Resource Requirement Monitoring

The CE management module monitors the requirements of users for CE resources periodically. That is, in a specified monitoring period, the CE management module extracts the maximum traffic volume in a TTI as the current maximum traffic volume. Then, the CE management module estimates the new maximum traffic volume in a TTI if the scheduler sends RG UP to the UE based on the current maximum traffic volume requirement. In this case, the CE management module calculates the new CE requirement and takes it as the CE requirement of the user.

In the calculation of the CE requirement, some resources are reserved for the user. Thus, the QoS can be ensured in the case of user rate fluctuation.

User Priority Queuing

The calculation of user priorities considers the following factors:

Happy Bit reported by the UE Actual rate obtained by the UE through real-time monitoring on the NodeB GBR requirement of the UE

SPI The queuing method is the same as that of the HSUPA fast scheduling algorithm. For details, see section "Fast Scheduling."

CE Resource Callback

CE resource callback is based on the monitoring of CE resource requirement of each user. For users with the currently allocated CE resources more than the calculated CE requirement, the required CE resources are reserved and the redundant CE resources are called back.

External Message Processing

The external message processing module processes the requests for CE resource allocation triggered by external messages, such as requests for adjusting CE resource allocation because of RL establishment, RL addition, RL reconfiguration, and compression mode start, and requests for increasing CE resources in the case of rate increase triggered by MAC-e scheduling.

If the available CE resources are sufficient, CE resources are allocated as required. If the available CE resources are insufficient, the CE resources allocated to other users can be preempted when some external messages arrive to ensure the access success rate or meet the rate adjustment requirement of the scheduling module. During the preemption process, the CE resources of low-priority users are preempted preferentially.

CE Resource Increase

If the CE resources requested by a user are more than the current allocated CE resources, resources must be increased. In addition, it is possible that the available CE resources do not meet the requirements of all users. In such a case, user priorities need to be considered. For details, see User Priority Queuing in this section. At the same time, the conditions of the serving cell also need to be considered.

If the serving cell of the user belongs to the current NodeB, the user is called serving user. If the serving cell of the user does not belong to the current NodeB, the user is called non-serving user. A serving user has a higher priority than a non-serving user because the QoS of the user mainly depends on the QoS obtained in the serving cell.

The CE resource increase consists of the following functions:

l CE resource adjustment among serving users After the connection is established, serving users cannot preempt resources mutually during the dynamic CE resource allocation. Therefore, it is possible that high-priority

users cannot obtain sufficient resources because low-priority users occupy a large amount of resources. In such a case, the resource fairness adjustment must be performed among serving RLs. The method is as follows:

If the current available CE resources do not meet the requirement of user rate increase, reduce the CE resources occupied by the serving user with the lowest priority to reserve resources and meet the rate increase requirement of high-priority users.

l Resource increase for serving users − If the monitoring of CE resource requirements shows that the CE resources allocated to the serving users are less than the CE resources requested, CE resources must be increased. − If the available resources meet the requirements of resource increase, CE resources are allocated according to the requirements of users. − If the available resources are insufficient to meet the requirements of resource increase, CE resources are allocated in descending order of user priorities.

l Resource increase for non-serving users After the resource allocation to serving RLs is complete, CE resources are allocated to non-serving users requesting resource increase in descending order of user priorities only when there are redundant resources.

Monitoring Cell CE

This section describes how to monitor the channel element (CE) conditions of the local cell, the local cell group, and the corresponding NodeB. Based on the monitoring result, the BSC6900 determines whether a UE can access the network.

Prerequisites

You have logged in to the LMT with an account authorized for this operation.

Procedure

1. Click Monitor on the LMT main page. The Monitor tab page is displayed.

2. On the Monitor Navigation Tree pane, choose Monitor > UMTS Monitoring > Cell Performance Monitoring. The Cell Performance Monitoring dialog box is displayed.

3. In the Cell Performance Monitoring dialog box, set Monitor Item to Cell CE. Set other parameters as required, and then click Submit.

NOTE:

A monitoring window is displayed, showing the real-time monitoring results in the form of list and chart. The task name is indicated in the title bar of the window.

In the chart, the X-coordinate represents the hour: minute: second. The Y-coordinate represents the number of CEs of the cell.

 

Configuring Dynamic CE Resource Management

This section describes how to activate, verify, and deactivate the optional feature WRFD-010638 Dynamic CE Resource Management.

Prerequisites

• Dependencies on Hardware

This feature does not depend on the hardware.

• Dependencies on Other Features

When this feature and "WRFD-01061208 HSUPA DCCC" are activated at the NodeB at the same time, "WRFD-01061208 HSUPA DCCC" automatically becomes ineffective at the NodeB.

• License

The license controlling this feature has been activated.

Context

To improve utilization efficiency of channel element (CE) resources, Huawei RAN introduces the Dynamic CE Resource Management feature. This feature helps to quickly adjust CE allocation by considering the Guaranteed Bit Rate (GBR) and the actual rate of a UE. During preemption of CE resources, this feature is used to allocate CE resources in a reasonable way, therefore ensuring preemption fairness.

Procedure

• Activation Procedure

1. The feature does not need to be activated.

• Verification Procedure

1. Start Tracing Messages on the Iub Interface on BSC6900 LMT and check whether the value of dynamic-CE-Switch-Private in NBAP_AUDIT_RSP is 1. If the value is 1, it indicates the feature is activated. Else, it indicates the feature is not activated. When the value of dynamic-CE-Switch-Private is 1, see Figure 1.

2. Figure 1 dynamic-CE-Switch-Private

• Deactivation Procedure

1. Run the BSC6900 MML command DEA UCELLHSUPA to deactivate HSUPA for the cell.

2. Set NodeB license control item the number of NodeBs with dynamic CE function enabled to 0 on M2000 client . Details see Allocating a License to NodeBs.

3. Run the BSC6900 MML command ACT UCELLHSUPA to activate HSUPA for the cell.

Example

//Deactivation procedure DEA UCELLHSUPA: CellId=80; ACT UCELLHSUPA: CellId=80;