TECHNICAL FIELD

The disclosed embodiments relate generally to wireless communication, and, more particularly, to method of handling Quality of Service (QoS) operation and EPS bearer operation errors in 5G new radio (NR) and 4G LTE systems.

BACKGROUND

The wireless communications network has grown exponentially over the years. A Long-Term Evolution (LTE) system offers high peak data rates, low latency, improved system capacity, and low operating cost resulting from simplified network architecture. LTE systems, also known as the 4G system, also provide seamless integration to older wireless network, such as GSM, CDMA and Universal Mobile Telecommunication System (UMTS). In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved Node-Bs (eNodeBs or eNBs) communicating with a plurality of mobile stations, referred to as user equipments (UEs). The 3rdgeneration partner project (3GPP) network normally includes a hybrid of 2G/3G/4G systems. With the optimization of the network design, many improvements have developed over the evolution of various standards. The Next Generation Mobile Network (NGMN) board, has decided to focus the future NGMN activities on defining the end-to-end requirements for 5G new radio (NR) systems.

Quality of Service (QoS) indicates the performance from the perspective of network users. In LTE Evolved Packet System (EPS), QoS is managed based on EPS bearer in the Evolved Packet Core (EPC) and the Radio Access Network (RAN). In 5G network, QoS flow is the finest granularity for QoS management to enable more flexible QoS control. The concept of QoS flow is like EPS bearer. All types of traffic mapped to the same LIE EPS bearer or to the same 5G QoS flow receive the same level of packet forwarding treatment (e.g., scheduling policy, queue management policy, rate shaping policy, RLC configuration etc.) Providing different QoS forwarding treatment requires separate 5G QoS flow. Each QoS flow may include multiple QoS rules consisting of QoS profile, packet filters, and precedence order.

When a QoS flow is added, the network can provide a QoS flow description IE to the UE, which comprises a list of QoS flow descriptions. Each QoS flow description comprises a QFI, a QoS flow operation code, a number of QoS flow parameters, and a QoS flow parameters list. Each parameter included in the parameters list consists of a parameter identifier that identifies the parameter. One of the parameter identifiers is the EPS bearer identity (EBI), which is used to identify the EPS bearer that is mapped to or associated with the QoS flow. When a QoS flow is deleted, all the associated EPS bearer context information that are mapped from the deleted QoS flow should be deleted from the UE and the network. Further, when creating a new mapped EPS bearer, if an existing mapped EPS bearer having the same EBI is associated with a PDU session, then a collision occurs on the EPS bearer. When inter-system changes from 5GS to EPS, UE behavior is undefined on how to handle such collision. Other semantic errors may also occur when QoS flow description is created, deleted, nor modified during the operation.

For PDU session establishment and modification procedures in 5GS, and for EPS bearer activation and modification procedures in EPS, all those procedures involve operations where QoS flows and EPS bearers may be created, deleted, or modified. Accordingly, operation errors may occur. A solution is sought for UE to handle the operation errors.

SUMMARY

Methods for handling QoS flow description and mapped EPS bearer operation errors are proposed. In a first novel aspect, UE receives a mapped EPS bearer context IE during a PDU session establishment or modification procedure. UE diagnoses whether an operation error occurs for a mapped EPS bearer context. If so, UE deletes the mapped EPS bearer context with a 5GSM cause. In a second novel aspect, UE receives a QoS flow description IE during a PDU session establishment or modification procedure. UE diagnoses whether an operation error occurs for a QoS flow description. If so, UE either rejects the modification command or deletes the QoS flow description with a 5GSM cause. In a third novel aspect, UE receives a QoS flow description IE during an EPS bearer activation or modification procedure. UE diagnoses whether an operation error occurs for a QoS flow description. If so, UE includes an ePCO/PCO IE with a 5GSM cause in an activation or modification accept message.

Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims.

