HSDPA Paging Indicator Channel Selection for Wireless Device State Transitions
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Solution Overview
Problem
In HSDPA networks, there is a challenge in reducing latency during state transitions of wireless transmit/receive units (WTRUs) in Cell_PCH and URA_PCH states, particularly due to the inability to configure high-speed downlink shared channels (HS-DSCH) in these states, lack of uplink communication for channel quality indication, and restricted base station scheduling flexibility.
Innovation Solution
Configuring WTRUs to select and receive paging messages based on Paging Indicator Channel (PICH) or High-Speed Shared Control Channel (HS-SCCH) information, with optional use of HS-PDSCH, and providing configuration information such as HS-DSCH radio network transaction identifiers and HARQ parameters through system information broadcasts, allowing for flexible scheduling and state transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If WTRUs in Cell_PCH and URA_PCH states use traditional paging channels (PCH/S-CCPCH), then they can receive paging messages, but state transition delays are increased and network performance is degraded
Solution Approach 1:
The patent combines the paging channel functionality with the high-speed downlink shared channel (HS-DSCH) by mapping the paging control channel (PCCH) onto HS-DSCH. This merging allows WTRUs in Cell_PCH and URA_PCH states to receive paging messages through the faster HS-DSCH channel instead of the traditional slower PCH, thereby reducing state transition delays while improving network performance.
Solution Approach 2:
The patent enables the HS-DSCH channel to serve dual purposes: carrying both data traffic and paging messages. By making HS-DSCH universal for both data and control information transmission, the system eliminates the need for separate paging channel infrastructure and achieves faster state transitions without compromising network performance.
2Loss of time
If HS-DSCH is configured in Cell_PCH and URA_PCH states, then state transition times are reduced, but device complexity and configuration requirements increase
Solution Approach 1:
The patent performs HS-DSCH configuration in advance during the cell update procedure. The network configures the HS-DSCH parameters, radio network temporary identifiers, and HARQ settings before the WTRU needs to transition states. This preliminary configuration action ensures that when paging occurs, the WTRU can immediately utilize the pre-configured HS-DSCH resources without additional delay, while the configuration complexity is managed during routine cell update procedures.
3Use of energy by moving object
If traditional paging procedures are used in Cell_PCH and URA_PCH states, then WTRUs can save battery power, but uplink communication for channel quality indication is lost
Solution Approach 1:
The patent enables feedback mechanisms by allowing WTRUs in Cell_PCH and URA_PCH states to send channel quality indicators (CQI) to the network through the enhanced uplink. The WTRU measures the quality of the received paging message on HS-DSCH and provides feedback about channel conditions, enabling the network to adaptively adjust transmission parameters while the WTRU remains in the low-power state.
Data Source
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AI summary
A method and a wireless transmit/receive unit, WTRU, to facilitate paging in high speed downlink packet access, HSDPA, wireless communications, the method comprising: when the WTRU is in one of a CELL PCH and URA PCH state: receiving, from a base station, HSDPA associated paging indicator channel, PICH, information elements comprising PICH information; compiling a list of candidate PICHs for HSDPA after receiving the information element; determining a value k corresponding to a number of candidates; calculating a selection index equal to:U_RNTI mod k, where U RNTI is a universal mobile telecommunications system (UMTS) terrestrial radio access network (UTRAN) radio network transaction identity (U-RNTI) of the WTRU; selecting a PICH information from the list of candidate PICHs based on the selection index; awakening from a sleep mode during paging occasions derived from the PICH information; monitoring for a paging indicator over a PICH using the selected PICH information; monitoring for a high speed dedicated shared channel, HS-DSCH, radio network transaction identity, H-RNTI; monitoring a high speed shared channel using the received H-RNTI; and returning to the sleep mode, if no H-RNTI is received.