Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W36/00—Hand-off or reselection arrangements
  • H04W36/0005—Control or signalling for completing the hand-off
  • H04W36/0055—Transmission or use of information for re-establishing the radio link
  • H04W36/0058—Transmission of hand-off measurement information, e.g. measurement reports
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W36/00—Hand-off or reselection arrangements
  • H04W36/0005—Control or signalling for completing the hand-off
  • H04W36/0055—Transmission or use of information for re-establishing the radio link
  • H04W36/0061—Transmission or use of information for re-establishing the radio link of neighbour cell information

Definitions

• the present invention relates generally to a Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system and, more particularly, to an improvement of a Serving and Neighbour cell Pathloss (SNPL) reporting mechanism of a User Equipment (UE) in a High Speed Uplink Packet Access (HSUPA) service/an uplink service of High Speed Packet Access enhancement (HSPA+) in the TD-SCDMA system.
• TD-SCDMA Time Division-Synchronous Code Division Multiple Access
• SNPL Serving and Neighbour cell Pathloss
• UE User Equipment
• HSUPA High Speed Uplink Packet Access
• HSPA+ High Speed Packet Access enhancement
• a high-throughput HSUPA service/a high-throughput uplink service of HSPA+ in a cellular communication system will cause a UE to generate high Rise over Thermals (RoTs) in a serving cell and neighbour cells of the UE. This problem gets worse for the neighbour cells when the UE is located on the edge of the serving cell.
• RoTs Rise over Thermals
• a Wideband Code Division Multiple Access (WCDMA) system introduces a physical channel called E-DCH Relative Grant Channel (E-RGCH) to solve the above-mentioned problem.
• E-RGCH E-DCH Relative Grant Channel
• the neighbour cells can use the E-RGCH to lower down the UE' s transmission power to reduce the RoTs in the neighbour cells.
• a UE reports SNPLs for a serving cell and neighbour cells of the UE to the serving cell periodically.
• Information about the SNPLs is used by the serving cell to control RoTs in the neighbour cells. For example, if a UE is close to a neighbour cell, a serving Base Station (BS) will give a less-power grant to the UE based on the reported SNPLs. As a result, the UE will not cause a high RoT in the neighbour cell.
• BS Base Station
• RoT control of neighbour cells greatly depends on frequency and accuracy of the SNPL reporting mechanism.
• the SNPL reporting mechanism as stated above works well in a situation where a UE stays in one cell at all times. However, when the UE makes a handover to another cell, the SNPL reporting mechanism will suffer a serious problem. This problem is described in detail below.
• a process relating to a handover of a UE can be divided into the following four stages.
• the UE sends a measurement report to a Radio Network Controller (RNC) coupled to the UE via a serving BS serving a serving cell of the UE . If it is judged by the RNC based on the measurement report that a handover of the UE from the serving cell to a target cell is required, the RNC sends a Radio Link Reconfiguration Prepare message to a target BS serving the target cell and sends a Radio Bearer Reconfiguration message to the UE. Upon receipt the Radio Bearer Reconfiguration message, the UE prepares for the handover.
• RNC Radio Network Controller
• the UE can make an uplink transmission for the HSUPA service/the uplink service of HSPA+. Also, the UE can measure SNPLs for the serving cell and neighbour cells and report the measured SNPLs to the serving BS.
• the UE executes the handover once it is ready for the handover. After the execution of the handover is finished, the UE sends a Radio Bearer Reconfiguration Complete message to the RNC. In this stage, the UE can neither make an uplink transmission for the HSUPA service/the uplink service of HSPA+ nor measure and report SNPLs.
• the RNC sends to the UE a Radio Resource Control Layer 3 (RRC L3) measurement control message including a neighbour cell list of the target cell.
• RRC L3 Radio Resource Control Layer 3
• the UE Upon receipt of this neighbour cell list, the UE starts to measure SNPLs for all of cells in this neighbour cell list.
• the UE can make an uplink transmission for the HSUPA service/the uplink service of HSPA+. But the UE can not measure and report SNPLs.
• the UE reports the measured SNPLs to the target BS . In other words, now the UE can normally operate in the target cell.
• the UE can make an uplink transmission for the HSUPA service/the uplink service of HSPA+ as well as measure and report SNPLs.
• a traffic volume of the UE in stages 1 to 4 is schematically shown.
• the traffic volume in stage 1 is low because the UE is located on the edge of the serving cell in this stage.
• the traffic volume in stage 2 equals zero because of the execution of the handover.
• the traffic volume in stage 3 is very low due to no SNPLs reporting.
• the traffic volume in stage 4 is high because the target BS can receive SNPLs in this stage .
• stage 3 the UE has to wait for the neighbour cell list of the target cell, to which the UE has switched, from the RNC because the UE needs to know the neighbour list before measuring the SNPLs. In other words, the UE can not start the SNPL measurement until it receives the neighbour list. Further, to keep network stability, the target BS will not give the UE a too much power grant before new valid SNPLs are measured.
• stage 3 may last as many as 250 ms, which has a great negative impact on the throughput of the UE for the HSUPA service/the uplink service of HSPA+, as indicated in Fig. 1.
• the method is performed by the UE and comprises steps of: receiving a neighbour cell list of the target cell from an RNC if it is judged by the RNC that the handover is required, where the RNC is coupled to the UE via a serving BS serving the serving cell; measuring SNPLs for all of cells in the neighbour cell list of the target cell in addition to SNPLs for all of cells in a neighbour cell list of the serving cell; and reporting the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the step of reporting further comprises steps of : reporting the measured SNPLs for all of cells in the neighbour cell list of the target cell to a target BS serving the target cell if the handover is successful; and reporting the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS if the handover is failed.
• the neighbour cell list of the target cell in the step of receiving is included in an RRC L3 measurement control message.
• the step of measuring is performed periodically.
• the step of measuring is performed once every 5ms, 10ms, or 20ms.
• the method is performed by the UE and comprises steps of: receiving a neighbour cell list of the target cell from an RNC if it is judged by the RNC that the handover is required, where the RNC is coupled to the UE via a serving BS serving the serving cell; measuring SNPLs for all of cells in a neighbour cell list of the serving cell; and reporting the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the step of reporting further comprises steps of: measuring SNPLs for all of cells in the neighbour cell list of the target cell and reporting the measured SNPLs for all of cells in the neighbour cell list of the target cell to a target BS serving the target cell, if the handover is successful; and reporting the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS if the handover is failed.
• the neighbour cell list of the target cell in the step of receiving is included in an RRC L3 measurement control message.
• the step of measuring is performed periodically.
• the step of measuring is performed once every 5ms, 10ms, or 20ms.
• a UE for improving an SNPL reporting mechanism in an HSUPA service/an uplink service of HSPA+ in a TD-SCDMA system for a handover of the UE from a serving cell to a target cell.
• the UE comprises one or more processing circuits.
• the one or more processing circuits are configured to: receive a neighbour cell list of the target cell from an RNC if it is judged by the RNC that the handover is required, where the RNC is coupled to the UE via a serving BS serving the serving cell; measure SNPLs for all of cells in the neighbour cell list of the target cell in addition to SNPLs for all of cells in a neighbour cell list of the serving cell; and report the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the one or more processing circuits are further configured to: report the measured SNPLs for all of cells in the neighbour cell list of the target cell to a target BS serving the target cell if the handover is successful; and report the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS if the handover is failed .
• the neighbour cell list of the target cell is included in an RRC L3 measurement control message.
• the one or more processing circuits are further configured to periodically measure the SNPLs for all of cells in the neighbour cell list of the target cell in addition to the SNPLs for all of cells in the neighbour cell list of the serving cell.
• the one or more processing circuit s are further configured to measure , once every 5ms , 10ms, or 20ms, the SNPLs for all of cells in the neighbour cell list of the target cell in addition to the SNPLs for all of cells in the neighbour cell list of the serving cell.
• a UE for improving an SNPL reporting mechanism in an HSUPA service/an uplink service of HSPA+ in a TD-SCDMA system for a handover of the UE from a serving cell to a target cell.
• the UE comprises one or more processing circuits.
• the one or more processing circuits are configured to: receive a neighbour cell list of the target cell from an RNC if it is judged by the RNC that the handover is reguired, where the RNC is coupled to the UE via a serving BS serving the serving cell; measure SNPLs for all of cells in a neighbour cell list of the serving cell; and report the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the one or more processing circuits are further configured to: measure SNPLs for all of cells in the neighbour cell list of the target cell and report the measured SNPLs for all of cells in the neighbour cell list of the target cell to a target BS serving the target cell, if the handover is successful; and report the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS if the handover is failed.
• the neighbour cell li ' st of the target cell is included in an RRC L3 measurement control message.
• the one or more processing circuits are further configured to periodically measure the SNPLs for all of cells in the neighbour cell list of the serving cell.
• the one or more processing circuits are further configured to measure, once every 5ms, 10ms, or 20ms, the SNPLs for all of cells in the neighbour cell list of the serving cell.
• an RNC for use with the UE as stated above.
• the RNC is configured to send the neighbour cell list of the target cell to the UE if the RNC judges that the handover is required.
• a TD-SCDMA system comprising at least the RNC as stated above and the UE as stated above.
• Fig. 1 schematically shows a traffic volume of a UE in stages 1 to 4 comprised in a process relating to a handover of the UE in the prior art
• Fig. 2 is a schematic block diagram of a portion of a TD-SCDMA system in which various embodiments of the present invention are implemented;
• Fig. 3 shows a flow chart illustrating a method of improving an SNPL reporting mechanism of a UE in an HSUPA service/an uplink service of HSPA+ in a TD-SCDMA system for a handover of the UE from a serving cell to a target cell according to an exemplary embodiment of the present invention
• Fig. 4 shows a flow chart illustrating a method of improving an SNPL reporting mechanism of a UE in an HSUPA service/an uplink service of HSPA+ in a TD-SCDMA system for a handover of the UE from a serving cell to a target cell according to another exemplary embodiment of the present invention.
• UE includes, but is not limited to, a user equipment, a mobile station, a mobile terminal, a mobile subscriber unit , a mobile TV client , apager, a cellular telephone, a Personal Digital Assistant (PDA), a smart phone, a text messaging device , a network interface card, a notebook computer , or any other type of user device capable of operating in a wireless environment.
• PDA Personal Digital Assistant
• BS includes, but is not limited to, a base station, a Node-B, or any other type of device with radio transmission/reception capabilities for providing radio coverage in a part of a TD-SCDMA system.
• the principle of the present invention is outlined first.
• the basic concept of the present invention is that in stage 1 the RNC sends a neighbour cell list of the target cell to the UE once the RNC judges that the handover of the UE from the serving cell to the target cell is required. In this way, the UE will know the neighbour cell list of the target cell in stage 1, rather than in stage 3 as stated in the process.
• stage 3 Knowing the neighbour cell list of the target cell earlier can facilitate stage 3 to be shortened or omitted. Specifically, since the UE knows the neighbour cell list of the target cell in stage 1, the UE does not need to wait for the neighbour cell list of the target cell from the RNC in stage 3. This will shorten stage 3.
• the UE can start to measure SNPLs for all of cells in the neighbour cell list of the target cell upon receipt of the neighbour cell list of the target cell. In this manner, the UE can report the measured SNPLs to the target BS in stage 4 upon completion of the handover, making stage 3 unnecessary .
• Fig. 2 is a schematic block diagram of a portion 200 of a TD-SCDMA system in which various embodiments of the present invention are implemented.
• the portion 200 comprises an RNC 202, a serving BS 204, a target BS 206, and a UE 208 including one or more processing circuits 210.
• the RNC 202 is coupled to the UE 208 via the serving BS 204 serving a serving cell before a handover of the UE 208. If the UE 208 makes a successful handover to a target cell, the RNC 202 will be coupled to the UE 208 via the target BS 206 serving the target cell .
• the one or more processing circuits 210 are configured to improve an SNPL reporting mechanism of the UE 208 in an HSUPA service/an uplink service of HSPA+ in the TD-SCDMA system for the handover of the UE 208 from the serving cell to the target cell. It should be understood that the one or more processing circuits 210 may comprise hardware, firmware, software, or any combination thereof.
• FIG. 3 there is shown a flow chart illustrating a method 300 of improving the SNPL reporting mechanism of the UE 208 in the HSUPA service/the uplink service of HSPA+ in the TD-SCDMA system for the handover of the UE 208 from the serving cell to the target cell according to an exemplary embodiment of the present invention.
• the method 300 is performed by the one or more processing circuits 210 in the UE 208.
• the method 300 begins with step 302 in which the UE 208 receives a neighbour cell list of the target cell from the RNC 202 if it is judged by the RNC 202 that the handover is required.
• the neighbour cell list of the target cell may be included in an RRC L3 measurement control message sent by the RNC 202.
• the UE 208 measures SNPLs for all of cells in the neighbour cell list of the target cell in addition to SNPLs for all of cells in a neighbour cell list of the serving cell. That is, on one hand the UE 208 measures the SNPLs for all of cells in the neighbour cell list of the serving cell as in the prior art. On the other hand, the UE 208 measures the SNPLs for all of cells in the neighbour cell list of the target cell in the meantime.
• the measuring in step 304 is performed periodically. For example, the measuring in step 304 is performed once every 5ms, 10ms, or 20ms.
• the measuring in step 304 is performed until stage 1 ends, and is not performed in stage 2 in which the UE 208 executes the handover.
• the UE 208 reports the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the UE 208 reports the measured SNPLs for all of cells in the neighbour cell list of the target cell to the target BS 206 if the handover is successful.
• stage 3 in the process as previously stated can be substantially omitted, which will make a great improvement on the throughput of the UE 208 for the HSUPA service/the uplink service of HSPA+.
• the UE 208 reports the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS 204 if the handover is failed, which makes the method 300 have little impact on the existing SNPL reporting mechanism.
• Fig. 4 shows a flow chart illustrating a method 400 of improving the SNPL report ing mechanism of the UE 208 in the HSUPA service /the uplink service of HSPA+ in the TD-SCDMA system for the handover of the UE 208 from the serving cell to the target cell according to another exemplary embodiment of the present invention.
• the method 400 is performed by the one or more processing circuits 210 in the UE 208.
• the method 400 begins with step 402, similar to step 302, in which the UE 208 receives a neighbour cell list of the target cell from the RNC 202 if it is judged by the RNC 202 that the handover is required.
• the neighbour cell list of the target cell may be included in an RRC L3 measurement control message sent by the RNC 202.
• the UE 208 measures SNPLs for all of cells in a neighbour cell list of the serving cell.
• the UE 208 has received the neighbour cell list of the target cell, it does not measure SNPLs for all of cells in the neighbour cell list of the target cell in this step. Instead, the UE 208 only measures the SNPLs for all of cells in the neighbour cell list of the serving cell as in the prior art.
• the measuring in step 404 is performed periodically. For example, the measuring in step 404 is performed once every 5ms, 10ms, or 20ms .
• the measuring in step 404 is performed until stage 1 ends, and is not performed in stage 2 in which the UE 208 executes the handover .
• the UE 208 reports the measured SNPLs based on a result of the handover for use with the HSUPA service/the uplink service of HSPA+.
• the UE 208 measures the SNPLs for all of cells in the neighbour cell list of the target cell and reports the measured SNPLs for all of cells in the neighbour cell list of the target cell to the target BS 206.
• stage 3 in the process as previously stated can be considerably shortened, which will make a significant improvement on the throughput of the UE 208 for the HSUPA service/the uplink service of HSPA+.
• the UE 208 reports the measured SNPLs for all of cells in the neighbour cell list of the serving cell to the serving BS 204 if the handover is failed, which makes the method 400 have little impact on the existing SNPL reporting mechanism.
• the pe formance of an HSUPA service/an uplink service of HSPA+ in a TD-SCDMA system for a handover of a UE is greatly improved on one hand.
• the introduction of the present invention has little impact on the current technical standard in a TD-SCDMA system .

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Citations (4)

• 2009
  • 2009-11-20 WO PCT/CN2009/001290 patent/WO2011060566A1/en active Application Filing
  • 2009-11-20 CN CN2009801231852A patent/CN102204347A/zh active Pending

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