frequency division multiple access

... 13 2.2.1CDMA (Code Division Multiple Access) .13 2.2.2CSMA/CD (Carrier Sense Multiple Access with Collision Detection): .13 2.2.3CSMA/CA (Carrier Sense Multiple Access with Collision ... Multiple Access with Collision Avoidance) 14 2.2.4TDMA (Time Division Multiple Access ) 14 2.2.5FDMA ( Frequency Division Multiple Access ) 15 3.Kỹ thuật truyền dẫn vô tuyến ... truyền liệu thời gian trễ lan truyền khác đầu cuối di động phân tán trạm 2.2.5 FDMA ( Frequency Division Multiple Access ) Đa truy xuất phân chia tần số Được dùng chủ yếu hệ thống radio chế TDMA,...

Ngày tải lên: 28/03/2014, 13:20

... common technologies with subtle differences.The main common technology is orthogonal frequency- division multiple access (OFDMA) - There are many good reasons for choosing OFDMA such as multipath ... bandwidths, the ability to handle different data rates, and the ability to easily combine with multiple antenna techniques Nhóm - The focus of this article is on the comparative use of OFDMA ... WIMAX AND LTE RESOURCE MAPPING FROM SUBCARRIERS Subcarriers are the smallest granular units in the frequency domain, OFDM symbol duration is the smallest granular unit in the time domain in OFDMA...

Ngày tải lên: 24/07/2015, 22:26

Ngày tải lên: 24/07/2015, 22:27

... keying (QPSK) Sophisticated multiple access technology like frequency division multiple access (FDMA), time division multiple access (TDMA) and code division multiple access (CDMA) also gained ... Code Division Multiple Access DFT Discrete Fourier Transform FDE Frequency Domain Equalizer FDMA Frequency Division Multiple Access FEC Forward Error Correcting FFT Fast Fourier Transform FH Frequency ... systems, multiple access technologies based on orthogonal frequency division multiplexing (OFDM) air interface were chosen [8] In the downlink, the popular orthogonal frequency division multiple access...

Ngày tải lên: 08/09/2015, 18:24

... Typical OFDM-based multiple access techniques include Time Division Multiple Access (OFDM-TDMA), Code Division Multiple Access (OFDM-CDMA or MC-CDMA) and Frequency Division Multiple Access (OFDM-FDMA) ... division multiple access MSE mean square error CFO carrier frequency offset OFDM orthogonal frequency division multiplexing CP cyclic prefix OFDMA orthogonal frequency division multiple access CRLB ... Orthogonal Frequency Division Multiplex (OFDM) is widely accepted as a major technique for many future broadband wireless systems OFDMA, a multiuser OFDM using Frequency Division Multiple Access...

Ngày tải lên: 14/09/2015, 14:03

... spread-spectrum multiple- access channels,” IEEE Journal on Selected Areas in Communications, vol 8, no 4, pp 641–649, 1990 [7] P A Hoeher and H Schoeneich, “Interleave -division multiple access from ... downlink multiple access capacity for Beyond 3G,” IEEE Communications Magazine, vol 43, no 1, pp 61–69, 2005 [10] J C Fricke, H Schoeneich, and P A Hoeher, “An interleavedivision multiple access ... values for the carrier frequency and the chip duration 6.2 MMSE channel estimation Let us now turn to MMSE channel estimation Numerical bit error results for frequency- flat and frequency- selective...

Ngày tải lên: 22/06/2014, 23:20

... of multiple- access system with multiple antennas at the base station Most previous studies are constrained to either fixed channel condition [11, 12] or ergodic capacity region [13] The space -division ... maximize the sum capacity of a time invariant Gaussian MIMO multiple- access channel The ergodic capacity region for MIMO multiple- access channel with covariance feedback has been studied in [13] ... with multiple antennas,” IEEE Transactions on Information Theory, vol 47, no 4, pp 1273–1289, 2001 [11] B Suard, G Xu, H Liu, and T Kailath, “Uplink channel capacity of space -division- multiple- access...

Ngày tải lên: 23/06/2014, 01:20

... understood orthogonal access techniques such as time division multiple access and frequency division multiple access Additionally, random access schemes such as carrier sense multiple access are examined ... Techniques for Code Division Multiple Access 23 2.1 Forms of Code Division Multiple Access 23 2.2 Direct Sequence Code Division Multiple Access ... contention-free multiple access is in how the channels are defined In time division multiple access (TDMA), channels are defined according to time slots In frequency division multiple access (FDMA),...

Ngày tải lên: 27/06/2014, 14:20

Ngày tải lên: 25/07/2014, 09:39

... understood orthogonal access techniques such as time division multiple access and frequency division multiple access Additionally, random access schemes such as carrier sense multiple access are examined ... Techniques for Code Division Multiple Access 23 2.1 Forms of Code Division Multiple Access 23 2.2 Direct Sequence Code Division Multiple Access ... contention-free multiple access is in how the channels are defined In time division multiple access (TDMA), channels are defined according to time slots In frequency division multiple access (FDMA),...

Ngày tải lên: 07/08/2014, 21:20

... Techniques for Code Division Multiple Access In the previous chapter, we reviewed the basic concepts of multiuser communications and the multiple access techniques used to allow multiple users to ... IML September 28, 2006 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) 1.2.1 ALOHA The most common contention-based methods are random access methods The first random access method was developed by Abramson ... application to ultra-wideband (UWB) systems 2.1 FORMS OF CODE DIVISION MULTIPLE ACCESS CDMA is also known as spread spectrum multiple access or SSMA because the use of spread spectrum waveforms...

Ngày tải lên: 07/08/2014, 21:20

... 28, 2006 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) FIGURE 2.4: Comparison of original/despread signal and spread signal spectra for DS/SS with square pulses 2.2.2 Multiple Access The DS/SS technique ... MOBK023-Buehrer.cls September 28, 2006 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) Frequency 38 BS B Ts Tc Tb Time FIGURE 2.10: Example of a time frequency plot for slow hopping (Tc : hop period, ... September 28, 2006 15:54 SPREAD SPECTRUM TECHNIQUES FOR CODE DIVISION MULTIPLE ACCESS 41 If we choose the frequency spacing to be an integer multiple of the hop rate for illustration purposes, we sample...

Ngày tải lên: 07/08/2014, 21:20

... hopping to be incorporated into the coding decision statistics 2.8 MULTIPLE ACCESS PERFORMANCE OF FREQUENCY- HOPPED CODE DIVISION MULTIPLE ACCESS Although the emphasis of this chapter is DS-CDMA, we ... additional channel estimation, which can be substantial 2.6 MULTIPLE ACCESS PERFORMANCE OF DIRECT SEQUENCE CODE DIVISION MULTIPLE ACCESS The previous section examined the performance of a single ... that we have not considered that arise in the multiple cell scenario P2: IML MOBK023-Buehrer.cls September 28, 2006 15:54 CODE DIVISION MULTIPLE ACCESS (CDMA) 10 K=1 K = 10 K = 20 K = 30 K =...

Ngày tải lên: 07/08/2014, 21:20

... CODE DIVISION MULTIPLE ACCESS In this section, we will discuss four key principles of CDMA systems, particularly cellular systems: interference averaging, statistical multiplexing, universal frequency ... 28, 2006 15:55 CODE DIVISION MULTIPLE ACCESS (CDMA) 3.1.4 Statistical Multiplexing The final fundamental CDMA concept that we will discuss in this section is termed statistical multiplexing, which ... 28, 2006 15:54 SPREAD SPECTRUM TECHNIQUES FOR CODE DIVISION MULTIPLE ACCESS 69 where P2 is the probability of any two users hopping to the same frequency in the same symbol duration For independent...

Ngày tải lên: 07/08/2014, 21:20

... P1: IML/FFX MOBK023-03 P2: IML MOBK023-Buehrer.cls 88 September 28, 2006 15:55 CODE DIVISION MULTIPLE ACCESS (CDMA) where I0 includes thermal noise power spectral density Including the effect ... IML/FFX MOBK023-03 P2: IML MOBK023-Buehrer.cls September 28, 2006 15:55 CELLULAR CODE DIVISION MULTIPLE ACCESS 89 Sector interference sources rm ro FIGURE 3.7: Illustration of out-of-cell interference ... (3.38) P1: IML/FFX MOBK023-03 P2: IML MOBK023-Buehrer.cls 90 September 28, 2006 15:55 CODE DIVISION MULTIPLE ACCESS (CDMA) In a similar fashion, we can show that var I P dm = · 1− Q 2κ e [σ ln(10)/10]2...

Ngày tải lên: 07/08/2014, 21:20

... ALOHA, CSMA, and busy tone multiple access (BTMA) [43] Note that unlike traditional narrowband random access protocols, channel access strategies for SS/PRNs allow for multiple simultaneous transmissions ... MOBK023-Buehrer.cls 118 September 28, 2006 15:55 CODE DIVISION MULTIPLE ACCESS (CDMA) indicator of the success or failure of packet access since multiple transmissions are possible Simply sensing ... Source Modulation and coding Frequency hopper Frequency dehopper Demodulation decoding Source Modulation and coding Frequency hopper Frequency dehopper Demodulation decoding Frequency dehopper Demodulation...

Ngày tải lên: 07/08/2014, 21:20

... September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) The decorrelator can also be extended to non-AWGN channels For example, the receiver can be used in flat and frequency selective Rician ... first P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 130 September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) addressed by Schneider [56] for both the synchronous and asynchronous AWGN ... based P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 132 September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) CDMA receivers Single user Matched filter Multiuser Adaptive filters Optimal...

Ngày tải lên: 07/08/2014, 21:20

... P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 148 September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) b Matched filter User - Σ+ - Matched filter User b1 - + Σ - Matched filter ... cancellation) P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 150 September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) Mathematically, we can represent the bit decisions for an S-stage parallel ... (5.79) P1: IML/FFX MOBK023-05 P2: IML MOBK023-Buehrer.cls 152 September 28, 2006 15:56 CODE DIVISION MULTIPLE ACCESS (CDMA) Now, if the estimates of b are correct we have ˆ ˆ Pr b = −1 | b = 1, b =...

Ngày tải lên: 07/08/2014, 21:20

... 17:14 CODE DIVISION MULTIPLE ACCESS (CDMA) [14] F A Tobagi and L Kleinrock, “Packet switching in radio channels: Part III—Polling and (dynamic) split-channel reservation multiple access, ” IEEE ... random -access packet switched code division multiple access channels,” IEEE Transactions on Communications, vol 29, pp 895–901, June 1981 [46] M Joa-Ng and I Lu, “Spread spectrum medium access ... Data Communications, pp 39–49, 1997 [17] Z J Haas and J Deng, “Dual busy tone multiple access (DBTMA)—a multiple access control scheme for ad hoc networks,” IEEE Transactions on Communications,...

Ngày tải lên: 07/08/2014, 21:20

... 1.2 Tiến trình triển khai công nghệ tiêu chuẩn hóa HSPA, HSDPA HSPA (High-Speed Packet Access: Truy cập tốc độ cao) công nghệ truyền dẫn không dây ứng dụng cho thiết bị thông tin di động...

Ngày tải lên: 02/06/2015, 17:26