Obviousness

Obviousness Analysis of US Patent 8976714 under 35 U.S.C. § 103

US Patent 8976714 claims a system and method for providing and acquiring system information (SI) messages in a wireless network, particularly addressing issues within LTE Time-Division Duplex (TDD) systems. The core invention lies in determining the start time or duration of a System Information (SI) window based on the availability for downlink transmissions, thereby preventing SI message blocking and ensuring equal reception reliability in TDD networks.

A person having ordinary skill in the art (PHOSITA) in wireless communication systems, at the time of the invention, would have been familiar with the 3GPP Long Term Evolution (LTE) standard and its associated technical specifications.

Combination of Prior Art References

The independent claims of US 8976714, specifically Independent Claims 1 (Network Element) and 5 (Wireless Subscriber Communication Unit), would likely be rendered obvious by combining the following prior art references:

1. 3GPP Technical Specification (TS) 36.331: This document outlines the existing system information acquisition procedures for LTE. The patent itself explicitly references TS 36.331 as the current standard that specifies the procedure for determining the start of an SI window [cite: "The current LTE standard in TS 36.331 specifies the following procedure to determine the start of the SI-window for a particular SI message."]. This procedure involves determining a number 'n' (transmission order), calculating an integer value 'x' based on 'n' and the si-WindowLength, and then deriving the subframe number '#a' and radio frame number using modulo and floor operations, specifically a = x mod 10 and SFN mod T = FLOOR(x/10) [cite: "x =( n− 1)* w", "a= x mod 10", "mod T =FLOOR( x/ 10), where: T is the SI-Periodicity of the concerned SI message."]. It also defines that SI messages are transmitted within periodically occurring time domain windows (SI-windows) and that the si-WindowLength is common for all SI messages and configurable [cite: "The SI messages are transmitted within periodically occurring time domain windows (referred to as SI-windows) using a dynamic scheduling mechanism.", "The length of the SI-window is common for all SI messages, and is configurable."].
2. 3GPP Technical Specification (TS) 36.211: This document defines the various frame configurations for TDD networks, explicitly detailing which subframes are allocated for downlink (D), uplink (U), or are special (S) [cite: "there are 7 different frame configuration types are defined in [TS 36.211] for TDD networks, which is represented below in Table 3.", "D represents a downlink subframe, U represents an uplink subframe and S represents a special frame, such that an ‘S’ frame can be used in both DL and UL transmission."]. This specification inherently provides the "availability for downlink transmissions" for any given TDD frame configuration.

Motivation to Combine

The motivation for a PHOSITA to combine the teachings of TS 36.331 and TS 36.211 stems directly from the problems identified and articulated within the background section of US 8976714 itself. The patent clearly states that the conventional SI acquisition procedure, as defined in TS 36.331, suffers from significant drawbacks when applied to TDD networks. Specifically, it highlights that "the calculation of SI-window and the starting point of each SI-window do not take into account the frame configuration (for example the downlink (DL)/uplink (UL) split) in a TDD network." [cite: "However, the calculation of SI-window and the starting point of each SI-window do not take into account the frame configuration (for example the downlink (DL)/uplink (UL) split) in a TDD network."].

This oversight, as detailed in the patent, leads to critical issues:

• Blocked SI Messages: The patent explicitly demonstrates, using various TDD frame configurations (e.g., Figures 3-8 and Tables 1-6), how SI messages can be entirely or partially blocked due to scheduled SI windows overlapping with uplink (UL) subframes [cite: "As a consequence, the delivery of system information in TDD network is not possible with some of the configurations allowed in the standard."]. It concludes that "transmission of some SI messages is impossible with some of the TDD frame configurations" [cite: "Thus, the above analysis illustrates that the operation of the currently specified SI acquisition procedure in TS 36.331, when applied to a TDD network with different frame configurations, is unacceptable. As explained, transmission of some SI messages is impossible with some of the TDD frame configurations."].
• Unequal Reception Reliability: The patent further explains that even when not entirely blocked, the effective length of SI windows can be reduced in TDD, leading to fewer repetitions of certain SI messages. This results in "unequal reception reliability of the SI-messages" compared to FDD networks, which is undesirable because "all the system information messages should be transmitted with the same robustness as all the system information messages are equally important for the correct operation of the UE." [cite: "According to the example shown above, transmission of SI-2, SI-4, SI-6 and SI-8 messages are more robust than the transmission of SI-1, SI-3, SI-5 and SI-7 messages due to their number of repetitions with in the SI-window. However, all the system information messages should be transmitted with the same robustness as all the system information messages are equally important for the correct operation of the UE."].

Given these clearly articulated problems in the prior art, a PHOSITA would have a strong motivation to modify the SI acquisition procedure defined in TS 36.331 to account for the TDD frame configurations specified in TS 36.211. The objective would be to resolve the issues of blocked SI messages and unequal reception reliability, thereby ensuring proper and robust operation of User Equipment (UEs) in TDD systems. The claimed solution, which involves determining the SI window start time or duration based on the "availability for downlink transmissions" (i.e., considering only DL subframes in the calculation, as exemplified by changing mod 10 to mod y where y is the number of DL subframes), directly addresses these known problems in a logical and straightforward manner. Such a modification would be an obvious design choice for a PHOSITA seeking to optimize SI acquisition in TDD LTE networks.