Obviousness

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11,032,000

This analysis identifies combinations of prior art references that would render the claims of US Patent 11,032,000 obvious to a person having ordinary skill in the art (PHOSITA) as of the priority date of December 27, 2006. The patent addresses challenges in wireless communication, particularly when adapting Time Division Duplex-Code Division Multiple Access (TDD-CDMA) systems to Frequency Division Duplex (FDD) operation where channel reciprocity is not guaranteed, thus affecting uplink power control and efficient shared channel access.

The independent claims (1, 7, 13, and 19) of US11032000 generally describe a system and method where:

• A User Equipment (UE) sends an uplink physical signal (referred to as a "UL_Beacon" in the patent description) for a base station to determine channel conditions.
• This UL_Beacon is sent in a time interval when the UE is not sending data over a physical uplink shared channel, and uses different resources than the shared channel.
• Multiple UEs can transmit their UL_Beacons in the same time interval.
• The UE receives control information (referred to as "PLCCH") from the base station on a physical control channel, based on the determined channel conditions.
• This physical control channel (PLCCH) is transmitted in the same time slot with other physical channels within a plurality of predetermined time slots in a downlink frame, while other time slots in the downlink frame do not include a physical control channel.
• The number of bits sent over the physical control channel is based on the number of fields of control information to be sent to the UE.

Combination of Prior Art References

A PHOSITA, seeking to address the problems outlined in US11032000, would have been motivated to combine the teachings of the following prior art references:

1. US20040170132A1 to Interdigital Technology Corporation ("Interdigital"): This patent application, titled "Path loss measurements in wireless communications," teaches measuring uplink path loss using uplink signals (e.g., pilots, probes) from a mobile station to determine uplink channel conditions and using this information to control the transmit power of the mobile station on the uplink. It directly addresses the need for explicit uplink channel condition determination and subsequent power control feedback.
2. US20030069020A1 to Ipwireless, Inc. ("Ipwireless"): This patent application, titled "System and method for physical shared channel allocation in a wireless communication system," describes methods for allocating physical shared channels efficiently. It highlights the importance of rapid and efficient access to shared channels, which implies the need for UEs to transmit at correct power with their first transmission.
3. US6611509B1 to Matsushita Electric Industrial Co., Ltd. ("Matsushita"): This patent, titled "CDMA/TDD mobile communication system and method," describes a TDMA/CDMA system operating in TDD mode, featuring a frame structure with dedicated time slots for uplink and downlink transmissions. It provides the foundational architectural context of a wireless system employing time division and code division multiplexing.
4. WO2006019263A2 to LG Electronics Inc. ("LG"): This patent application, titled "A method for establishing fast feedback channel and transmitting information in a wireless communication system," teaches the establishment of fast feedback channels, for example, for high-speed downlink packet access (HSDPA). This reinforces the concept of dedicated feedback mechanisms for channel conditions.
5. US20010048711A1 to Huawei Technologies Co., Ltd. ("Huawei"): This patent application, titled "Pilot synchronization channel structure for CDMA mobile communication system," describes the use of pilot channels in CDMA systems, where multiple users may transmit in the same interval, distinguished by codes.

Motivation for Combination and Obviousness Reasoning

A PHOSITA, striving to evolve a TDD TD-CDMA system (as understood from Matsushita) to operate in FDD mode while addressing the loss of channel reciprocity and maintaining efficient shared channel access, would have been motivated to combine the teachings of Interdigital, Ipwireless, Matsushita, LG, and Huawei for the following reasons:

1. Uplink Physical Signal for Channel Conditions (UL_Beacon) in Non-Data Intervals with Different Resources:

   • Interdigital clearly teaches the necessity of measuring uplink path loss via uplink signals from a mobile station to achieve accurate uplink power control, especially when channel reciprocity is not available or reliable. This directly informs the PHOSITA of the need for an "uplink physical signal" (UL_Beacon) for channel condition determination by the base station.
   • Ipwireless emphasizes efficient allocation and rapid access to shared uplink channels. A PHOSITA would recognize that to achieve rapid access, UEs need up-to-date channel condition knowledge to transmit at the correct power immediately. Relying solely on data transmissions for channel estimation would introduce latency. Therefore, it would be an obvious design choice to send a dedicated uplink physical signal (UL_Beacon) in a time interval when the UE is not sending information over the physical uplink shared channel, ensuring continuous or frequent channel condition updates without occupying valuable data resources.
   • The concept of different resources for control signals (like pilots or beacons) versus data channels is well-established in wireless communication, as seen in Matsushita's TDMA frame structure with dedicated time slots and general CDMA principles of using different codes for different channels.

2. Multiple UEs Transmitting UL_Beacons in the Same Time Interval:

   • Huawei teaches the use of pilot channels in CDMA where multiple entities may transmit simultaneously, distinguished by codes, for synchronization. Extending this concept to UL_Beacons for channel condition measurement, where multiple UEs transmit their respective signals in the same time interval (e.g., using different spreading codes in a CDMA system or distinct preamble sequences in a TDMA slot), would be an obvious way to scale the system and efficiently collect channel information from multiple users simultaneously.

3. Downlink Physical Control Channel (PLCCH) for Feedback Based on Channel Conditions:

   • Interdigital explicitly teaches sending control information back to the mobile station for transmit power control based on uplink channel measurements. This provides the basis for the PLCCH carrying control information.
   • LG further elaborates on establishing fast feedback channels, indicating the general importance of such channels in modern wireless systems.
   • The notion that the control information is "based on the determined channel conditions" is a fundamental aspect of closed-loop power control, widely known in the art (e.g., from early CDMA power control patents like US5056109A).

4. PLCCH Transmitted in Same Time Slot with Other Physical Channels in Predetermined Time Slots:

   • Matsushita and Ipwireless, combined with general knowledge of TDMA/CDMA resource management, would make this element obvious. Matsushita introduces the concept of a TDMA frame structure with time slots. Ipwireless focuses on efficient shared channel allocation. A PHOSITA would recognize that to efficiently utilize downlink resources and to provide the necessary control feedback without dedicated, constant channels for every UE, multiplexing a physical control channel (PLCCH) with other physical channels (e.g., data channels) within predetermined time slots in a downlink frame is an efficient design choice. This could be achieved via code-division multiplexing within a shared time slot, a common technique in CDMA systems. Limiting the presence of the PLCCH to "predetermined time slots" (i.e., not every time slot) is a logical resource optimization to match the required feedback rate, which is an obvious engineering consideration.

5. Number of Bits in PLCCH Based on Number of Fields of Control Information:

   • This is a fundamental principle of communication system design: the capacity of a control channel is dictated by the amount and type of information (fields) it needs to convey. A PHOSITA would trivially match the number of bits to the complexity and quantity of control commands (e.g., power up/down, rate adaptation commands).

Conclusion

Therefore, the combination of US20040170132A1 (Interdigital) for explicit uplink channel condition measurement and feedback, US20030069020A1 (Ipwireless) for efficient shared channel access necessitating continuous channel knowledge, US6611509B1 (Matsushita) for TDMA/CDMA frame structures and TDD-to-FDD evolution context, WO2006019263A2 (LG) for fast feedback channels, and US20010048711A1 (Huawei) for simultaneous pilot transmissions, would render the independent claims of US Patent 11,032,000 obvious to a PHOSITA. The motivation to combine these references would stem from the known challenges of maintaining robust uplink power control and low-latency shared channel access when operating a system, originally designed for TDD, in an FDD environment where channel reciprocity cannot be relied upon.