Obviousness

US patent 10136416, "Communicating on a shared channel in a wireless network," is subject to an obviousness analysis under 35 U.S.C. § 103, considering combinations of prior art references discussed within the patent's own background section. The patent itself identifies problems with existing solutions, providing motivation for a person having ordinary skill in the art (PHOSITA) to combine known elements.

Identified Prior Art References from Patent Background:

1. Traditional UMTS FACH operation (A): This describes the Forward Access Channel (FACH) as a downlink transport channel using pre-defined, reserved physical resources (codes, timeslots) broadcast on the Broadcast Channel (BCH). The FACH is controlled by the Radio Network Controller (RNC) and is not always transmitted, but its dedicated timeslot remains reserved, leading to inefficient resource use when inactive.
2. UMTS Paging Channel (PCH) and Paging Indicator Channel (PICH) operation (B): This details the PICH, which comprises multiple indicator bits. User Equipment (UEs) in an idle state periodically decode the PICH to check if an associated indicator bit is set. If so, the UE then reads the PCH. This mechanism is primarily for battery saving, informing the UE whether to activate its radio for reading the PCH.
3. Known solution for FACH timeslot reuse by mapping FACH onto HS-DSCH (C): This describes a method where FACH messages are transmitted on the High Speed Downlink Shared Channel (HS-DSCH). In this solution, the Node B controls the FACH, and the traditional FACH timeslot becomes an HS-DSCH timeslot. The content for HS-DSCH is allocated via the Shared Control CHannel for the HS-DSCH (HS-SCCH), which broadcasts a FACH-ID. UEs monitor the FACH by decoding the HS-SCCH using this FACH-ID. When no FACH messages are requested, the Node B uses all HS-DSCH resources for traffic data (i.e., the resources are re-allocated). However, a significant problem with this solution is that both the HS-SCCH and HS-DSCH must be used to transmit a FACH message, each requiring approximately 33% of the Node B transmit power, resulting in increased power consumption compared to a dedicated FACH timeslot.

Obviousness Analysis for Claims 1 and 14 (Network Node Method/Apparatus):

Claim 1 describes a method by a cellular communication network node to dynamically allocate resources for a direct signalling channel. It involves determining if a message is to be transmitted, and if so, scheduling the message in a unit of resource for a direct signalling channel and setting an indicator bit. If no message, the unit of resource is re-allocated for another channel. Claim 14 describes the corresponding network node.

Combination of Prior Art (A + B + C):

1. Determining whether at least one message is to be transmitted: This is taught by prior art (C), where the Node B implicitly makes this determination based on requests from the RNC.
2. Scheduling the at least one message for transmission in at least one unit of resource allocated to at least one direct signalling channel: This is taught by prior art (A) (Traditional UMTS FACH), which uses dedicated resources for FACH messages.
3. Setting at least one direct signalling channel indicator bit for transmission: This concept is taught by prior art (B) (PICH), which uses indicator bits to signal PCH activity. While PICH signals paging, adapting this known mechanism to signal the activity of another direct signalling channel like FACH would be an obvious design choice for a PHOSITA. Prior art (C) also includes a form of indication (FACH-ID in HS-SCCH) for FACH content within a shared channel.
4. Re-allocating at least one unit of resource allocated for use by the at least one direct signalling channel for use by at least one channel other than the direct signalling channel: This is taught by prior art (C), where Node B re-allocates HS-DSCH resources for traffic data when no FACH messages are present. Prior art (A) also notes the inefficiency of reserved, unused FACH timeslots, implicitly desiring re-allocation.

Motivation to Combine:
The patent itself highlights the disadvantages of existing solutions, providing explicit motivation for a PHOSITA to combine these elements. Prior art (A) is criticized for its inefficient use of reserved physical resources when the FACH is lightly used. Prior art (C), while solving the resource efficiency issue, introduces a new problem of increased power consumption due to requiring both HS-SCCH and HS-DSCH for FACH messages.

A PHOSITA would be motivated to address these identified problems by seeking a solution that combines the power efficiency of a single, dedicated FACH transmission (from A) with the resource efficiency of dynamic reallocation (from C), while avoiding the power overhead associated with the HS-DSCH mapping solution (C). To enable dynamic reallocation of a dedicated FACH resource, the network needs to signal its activity to the UEs. Prior art (B) provides a well-established and analogous mechanism for signaling channel activity (PCH) to UEs using indicator bits, which is employed for efficiency (e.g., battery saving). It would be obvious to adapt this known indicator bit mechanism from PICH for PCH to FACH to inform UEs when to monitor the FACH's dedicated resources versus when those resources are available for other channels (like HS-DSCH). This combination results in a system that improves both power and resource efficiency, directly addressing the stated problems in the prior art.

Obviousness Analysis for Claims 20 and 24 (Wireless Communication Unit Method/Apparatus):

Claim 20 describes a wireless communication unit (UE) with logic for receiving a signaling message and a direct signalling channel indicator bit, and for modifying its allocated resources based on the status of that bit. Claim 24 describes the corresponding method performed by the UE.

Combination of Prior Art (B + C):

1. Receiving a signalling message allocating a first set of resources: This is a general function of a UE in any cellular communication system and would be known.
2. Receiving at least one direct signalling channel indicator bit on a communication channel, the at least one direct signalling channel indicator bit allocating a direct signalling channel: This is directly taught by prior art (B), where a UE receives indicator bits on the PICH to determine PCH activity. Furthermore, prior art (C) describes UEs receiving and processing the FACH-ID within the HS-SCCH to identify FACH messages within the HS-DSCH.
3. Modifying the wireless communication unit's first set of resources in response to a status of the at least one direct signalling channel indicator bit: Prior art (B) teaches the UE to modify its behavior (e.g., power up its radio, decode PCH) in response to a PICH indicator bit. Similarly, prior art (C) shows the UE modifying its interpretation and use of HS-DSCH resources (as FACH or traffic) based on the FACH-ID. The patent explicitly states that the UE is able to use the FACH indicator bit "to modify, for example, the HS-DSCH resource allocation."

Motivation to Combine:
The motivation for the UE to perform these actions is inherently linked to the network's dynamic signaling and resource allocation strategy. The patent highlights a problem in 3GPP systems where the same number of codes must be allocated to a UE across all timeslots due to signaling restrictions. To overcome this, the patent proposes signaling the FACH's activity to the UE, allowing the UE to use this indication to "modify...the HS-DSCH resource allocation."

A PHOSITA would find it obvious to configure a UE to monitor such a FACH indicator bit (using known methods from PICH for PCH, or HS-SCCH for FACH-in-HS-DSCH) and to accordingly adjust its resource processing and interpretation. This adjustment enables the UE to correctly use its allocated resources, whether for receiving FACH messages or other traffic (e.g., HS-DSCH), thereby improving overall resource utilization and flexibility. The inherent need for the UE to correctly interpret the dynamically changing shared channel content provides the clear motivation for this functionality.

In conclusion, the methods and apparatus described in US patent 10136416 would likely be obvious to a PHOSITA, given the clear motivations to address identified problems in the prior art by combining existing techniques in a predictable manner.