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HSPA+, or Evolved High-Speed Packet Access, is a technical standard for wireless, broadband telecommunication. HSPA+ enhances the widely used WCDMA (UMTS) based 3G networks with higher speeds for the end user that are comparable to the newer LTE networks. HSPA+ was first defined in the technical standard 3GPP release 7 and expanded further in later releases. In the United States, it is commonly available under AT&T Mobility and T-Mobile US. ==Speeds== HSPA+ provides an evolution of High Speed Packet Access and provides data rates up to 168 Megabits per second (Mbit/s) to the mobile device (downlink) and 22 Mbit/s from the mobile device (uplink). Technically these are achieved through the use of a multiple-antenna technique known as MIMO (for "multiple-input and multiple-output") and higher order modulation (64QAM) or combining multiple cells into one with a technique known as Dual-Cell HSDPA. The 168 Mbit/s and 22 Mbit/s represent theoretical peak speeds. The actual speed for a user will be lower. In general, HSPA+ offers higher bitrates only in very good radio conditions (very close to cell tower) or if the terminal and network both support either MIMO or Dual-Cell HSDPA, which effectively use two parallel transmit channels with different technical implementations. The higher 168 Mbit/s speeds are achieved by using multiple carriers with Dual-Cell HSDPA and 4-way MIMO together simultaneously. The technology also delivers significant battery life improvements and dramatically quicker wake-from-idle time – delivering a true always-on connection. HSPA+ should not be confused with LTE, which uses a new air interface based on OFDMA technology. HSPA+ is an evolution of HSPA that upgrades the existing 3G network and provides a method for telecom operators to migrate towards 4G speeds without deploying a new radio interface. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Evolved HSPA」の詳細全文を読む スポンサード リンク
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